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Posted: 5/29/2017 12:21:06 AM EDT
[Last Edit: Eagle_19er]
With the proliferation of both SBR's and suppressors in recent years, I thought it would be appropriate to gather some loads and run some tests. I ran a limited test at the end of 2015/beginning of 2016 that can be found here but wanted to expand and see how shorty's would do with more options.
Over the past year (plus), I've managed to gather 41 factory loads and enough to test 10 rounds of each in a 10.5", 11.5", 12.5" and 14.5" barrel to establish a baseline velocity. They run the gamut from 55gr Wolf Polyformance steel case to a few flavors of heavy OTM loads. It's by no means an exhaustive list of everything available in 5.56, but these loads cover many of the popular "off the shelf" (and a few more obscure) loads that many of us shoot at the range and/or depend on for self defense, hunting or duty. I completed the 10.5" tests today and am starting a thread with these results. Future posts will include the other barrel length results, a post when the tests are complete with side by side comparisons of the rounds and maybe even JBM ballistic charts as I have time to plug in the data. At this point, I plan on having all this testing done by mid-summer 2017. Enough bloviating, on to the test! The Rifle: Noveske 10.5" Switchblock w/CHF barrel cerakoted in Midnight Bronze. Geissele SSA trigger. SiCo Omega suppressor attached with an ASR FH. (This rifle was previously duracoated but I hated it so I blasted and re-did the whole thing, including a new optic and stock) Big boy Legos FTW.  Attached FileThe Ammo:  Attached FileThe Chronograph: MasterChrony, 12 feet from the muzzle. Atmospherics: Air Temp: 66-70 degrees Humidity: 40% Dewpoint: 45 degrees Pressure: 29.74 (steady) Elevation: 1030' The Results: I calculated average velocity, extreme spread and standard deviation using Excel. I broke up ammo by type and sometimes weight into categories that made sense to me.  Attached File Attached File Attached File |
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Posted: 5/29/2017 12:21:33 AM EDT
[Last Edit: Eagle_19er]
[#1]
I got out this morning for the 11.5" barrel tests. Results in this post! There were a few surprises where velocity actually dropped on a couple of the loads but on most there was an increase with the 11.5" barrel.
The Rifle: Parts build around an 11.5" Faxon Big Gunner Midlength barrel. LaRue MBT-2S trigger. Sico Omega suppressor. Cerakoted in Magpul FDE.  Attached FileThe Chronograph: MasterChrony, 12 feet from the muzzle. Atmospherics: Air Temp: 71-77 degrees Humidity: 41% Dewpoint: 54 degrees Pressure: 29.88 (steady) Elevation: 1030' The Results: I calculated average velocity, extreme spread and standard deviation using Excel.  Attached File Attached File Attached File |
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Posted: 5/29/2017 12:21:53 AM EDT
[Last Edit: Eagle_19er]
[#2]
12.5" tests are done! I saw a very nice jump in velocity for both 64gr and 75gr Gold dots, and across the board with pretty much all the ammo really.
The Rifle: BCM Standard 12.5" cerakoted in Patriot Brown. Geissele SSA trigger. SiCo Omega suppressor attached with an ASR FH.  Attached FileThe Chronograph: MasterChrony, 12 feet from the muzzle. Atmospherics: Air Temp: 72-78 degrees Humidity: 44% Dewpoint: 55 degrees Pressure: 29.82 (steady) Elevation: 1030' The Results: I calculated average velocity, extreme spread and standard deviation using Excel. I broke up ammo by type and sometimes weight into categories that made sense to me.  Attached File Attached File Attached File |
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Posted: 5/29/2017 12:22:08 AM EDT
[Last Edit: Eagle_19er]
[#3]
Surprise! My plans for today got cancelled and the weather was right so I got out for the 14.5" test. See the results below.
The Rifle: BCM 14.5" BFH midlength barrel, Geissele SSA-E trigger. Gun cerakoted in Federal Standard Field Drab (aka baby poop brown)  . SiCo Omega suppressor attached with an ASR FH.
 Attached FileThe Chronograph: MasterChrony, 12 feet from the muzzle. Atmospherics: Air Temp: 72-79 degrees Humidity: 44% Dewpoint: 57 degrees Pressure: 29.69 (steady) Elevation: 1030' The Results: It seems the biggest jump I got in velocities was from 11.5" to 12.5" barrels. Going from 12.5" to 14.5" still shows an increase, but the rate of increase actually slowed for many of the loads.  Attached File Attached File Attached File |
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Posted: 5/29/2017 12:22:39 AM EDT
[Last Edit: Eagle_19er]
[#4]
With all the testing done as of 6/17/17, I took some time to compile the results in a side by side comparison. Please note, there was a metric TON of copy/pasting going on in Excel to achieve this view of the tests. I spot checked quite a few of the data points to ensure accuracy but if you notice a mistake from the raw data, please IM me and I'll be glad to correct the error and re-post a corrected image. --The raw data in the first 4 posts is correct in all respects.
That said, there have been questions raised later in this thread about certain loads and their performance in the different barrel lengths. In some cases, velocity dropped a few FPS, even though the barrel length increased (being the main question.) The internal and external variables that go into this type of test are bound to produce some statistical anomalies so please don't take these results as the end all/be all of velocity tests for YOUR barrel. This data can be useful as a guide however...more of a starting point to find some loads you want to see if your barrel 'likes'. If you're depending on this ammo to perform in a self defense or hunting situation, it's always best to test it for yourself. Personally, I like 62gr Fusion MSR and Black Hills 77gr TMK for their performance in my barrels, with all three flavors of Gold Dots being acceptable in my longer SBR's and both Barnes 62gr TSX and 70gr TSX being acceptable substitutes in all my barrel lengths. As always though, YMMV. Self defense ammo (all weights) summary:  Attached File55-62gr FMJ ammo summary:  Attached FileSteel Case (all weights) summary:  Attached File |
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Posted: 5/29/2017 12:22:49 AM EDT
[Last Edit: Eagle_19er]
[#5]
This post contains ballistics tables for many of the popular rounds found in this velocity test. The tables were calculated using a popular ballistics program on the internet. I inputted the known variables including the velocity, ballistic co-efficient, weight of the bullet and weather conditions with a 50yard zero for all barrel lengths tested. BC's were all found on the manufacturer's or bullet maker's website. The windage in the charts was calculated using a 10mph wind at 90 degrees (full value). Bullet drop and energy of the round were highlighted in red for easy reference. The graphic chart depicts bullet drop out to 500 yards.
*I'm starting with these 8 self defense/hunting loads because they seem to be driving the most conversation in this thread and they are also the rounds I'm most interested in seeing this data on. I'll probably add more to this post. If there's a particular round I tested that you're interested in seeing ASAP, let me know and I can run the numbers and post it. UPDATE 10/18/19: Image hosting expired for the images in this post so I combined a couple of the images into a single image so as to upload them through Arf's native hosting system. I'll have to figure out how to get the rest of them back up, as I'm limited to 5 images per post. Black Hills 77gr Tipped Matchking Ballistic Co-efficient .420 (G1) Black Hills tested this bullet to expand down to 1900fps.  Attached FileIMI 77gr OTM LR Mod1 (Razor Core) Ballistic Co-efficient .362 (G1) Expansion down to 2100fps? (Anecdotal, number found on the internet).  Attached FileFederal Fusion MSR 62gr Ballistic Co-efficient .315 (G1) The Chopping Block tested this ammo and got about 190% expansion (.384") @ 1700fps.  Attached FileBarnes 62gr VOR-TX TSX Ballistic Co-efficient .287 (G1) 1900fps expansion floor according to Barnes.  Attached FileBarnes 70gr VOR-TX TSX Ballistic Co-efficient .314 (G1) 1800fps expansion floor according to Barnes.  Attached FileSpeer 55gr Gold Dot Ballistic Co-efficient .222 (G1) 1800fps expansion threshold? (No confirmation) Speer 64gr Gold Dot Ballistic Co-efficient .270 (G1) 1800fps expansion threshold? (No confirmation) Speer 75gr Gold Dot Ballistic Co-efficient .400 (G1) 1800fps expansion threshold? (No confirmation). |
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Posted: 5/29/2017 2:04:14 AM EDT
[#6]
Very interesting data.
IMI ball 55gr and 62gr moves right along. I am going to have to compare some figures from my data. |
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Posted: 5/29/2017 2:08:45 AM EDT
[#7]
Awesome thread. Thank you OP!
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Posted: 5/29/2017 6:19:31 AM EDT
[#8]
Awesome, thank you!
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SC, USA
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Posted: 5/29/2017 6:35:15 AM EDT
[#9]
Great post I will have to spend more time on it in a couple days. My Speer GD are ~ the same speed as your testing but all of your IMI are 150 FPS faster than my recent testing on my 10.5", no suppressor.
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Posted: 5/29/2017 8:55:00 AM EDT
[#10]
Awesome
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Posted: 5/29/2017 9:15:30 AM EDT
[#11]
Great info, thank you. That 55gr TSX is a lot slower than I'd have thought.
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OK, USA
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Posted: 5/29/2017 10:44:39 AM EDT
[#12]
This is great data keep it up! I'm very underwhelmed at my Gold Dot 75's, but that's about what I should have expected I guess. They still look to retain expansion velocity for a good 200m or so.
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Posted: 5/29/2017 1:36:40 PM EDT
[#13]
Quote HistoryOriginally Posted By p2tharizo:
Awesome thread. Thank you OP! |
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Posted: 5/29/2017 2:06:44 PM EDT
[#14]
Thanks all! I'm really looking forward to the other barrel tests.
Originally Posted By bfoosh06:
Very interesting data. IMI ball 55gr and 62gr moves right along. I am going to have to compare some figures from my data. Originally Posted By CountryGuy:
Great post I will have to spend more time on it in a couple days. My Speer GD are ~ the same speed as your testing but all of your IMI are 150 FPS faster than my recent testing on my 10.5", no suppressor. The suppressor won't account for ~150fps. I wonder what the difference is. What's your lot #'s? Mine are 249/F (55gr), 223/6 (62gr) & 237/E (77gr OTM). Originally Posted By Eric802:
Great info, thank you. That 55gr TSX is a lot slower than I'd have thought. Originally Posted By doty_soty:
This is great data keep it up! I'm very underwhelmed at my Gold Dot 75's, but that's about what I should have expected I guess. They still look to retain expansion velocity for a good 200m or so. |
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Posted: 5/29/2017 4:48:43 PM EDT
[#15]
OP did you run unsuppressed for any of these products on the same day to see if the can is adding velocity? I gained about 30-40 fps from a .308 (21" Fal) going no can to can..
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Posted: 5/29/2017 5:02:52 PM EDT
[#16]
Thanks for posting your findings. I was planning on running the 64 grain Gold Dots as my HD ammo in my 10.5" suppressed AR but will have to find the Fusion MSR as that was quite the velocity difference. I believe they use the same bullet but if I am wrong please let me know.
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SC, USA
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Posted: 5/29/2017 5:24:32 PM EDT
[#17]
Quote HistoryOriginally Posted By CountryGuy:
Great post I will have to spend more time on it in a couple days. My Speer GD are ~ the same speed as your testing but all of your IMI are 150 FPS faster than my recent testing on my 10.5", no suppressor. Ammunition My Avg Vel Your Avg Vel Speer GD- 55 2612.7 2625 Speer GD- 64 2293.7 2324 Speer GD- 75 2213.7 2239 IMI M193- 55 2672.7 2856 IMI M855- 62 2637.3 2721 IMI- OTM Mod 1 2448.9 2403 Fed AE XM855 2657.7 2601 |
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Posted: 5/29/2017 6:39:50 PM EDT
[#18]
Quote HistoryOriginally Posted By Buffman_LT1:
OP did you run unsuppressed for any of these products on the same day to see if the can is adding velocity? I gained about 30-40 fps from a .308 (21" Fal) going no can to can.. |
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Posted: 5/29/2017 6:46:32 PM EDT
[#19]
Quote HistoryOriginally Posted By FiremanFrank:
Thanks for posting your findings. I was planning on running the 64 grain Gold Dots as my HD ammo in my 10.5" suppressed AR but will have to find the Fusion MSR as that was quite the velocity difference. I believe they use the same bullet but if I am wrong please let me know. ...I wish MSR was still available for $.50/rd like fall 2015. 64gr GD is probably the most similar you can get to that for the price, just be aware of the velocity differences in the current batch on the market. |
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SC, USA
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Posted: 5/29/2017 7:55:59 PM EDT
[#20]
This is a bit off topic overall but on topic for the Speer GD 64 grain low velocity. Speer produces a 135 grain GD for .38 Special +P designed specifically for short barrels. Relative to other .38 Sp. GD bullet offerings I have from other OEM's, the 135 is also down on power significantly and a disappointment to me. For anyone interested, see the chart at the bottom of this thread: https://www.ar15.com/forums/t_5_20/173203_2-barrel----38-Special-vs-9mm-.html. The GD 135 grain tested is new that I just received. These GDs are hard to find usually so I am pretty sure it is current production. It would be interesting if someone had some older 223 GD 64 grain and some older .38 Sp. +P 135 grain for chrono comparison.
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SC, USA
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Posted: 5/30/2017 1:53:08 PM EDT
[#21]
OP: Yours and my chrono results out of 10.5" barrels have really made me take a hard look at my initial primary and secondary ammunition stock for the short barrel 556. Your Federal Fusion MSR 62 grain results provide 881 ft. pounds of energy and my Speer GD 55 grain results provide 833 ft. pounds of energy. Not a lot of difference but in the case of short barrels and some distance- maybe enough, depending. Online pricing for the Fusion MSR is ~ $1/round plus shipping and I typically purchase no less than 400 rounds of any 223 defensive type ammunition at a time and usually more if I need to test something new- like the Fusion MSR 62 grain, in this case.
I feel comfortable Fusion MSR will chronograph similarly in my 10.5" barrel as in yours with the results we both have. My 556 stamped barrels that have been measured and reamed as required to 556 specs, like any quality ammunition I have fed them and shoot reasonably small groups of everything- meaning they are more accurate than I. Have you compared how the Fusion MSR group on paper vs. 55 grain Gold Dots or anything else? Since a short barrel firearm is typically for shorter ranges, and in my case 50 yards - 75 yards, I am rearranging my short barrel ammunition stock from 75/77 grains as primary to the GD 55 grain as primary until I can find a good sale on Fusion MSR and test. Alternatively, I will be comfy with my GD 55s in this case. For the 16" carbine, my testing confirmed 75 grain GDs and 77 gr. IMI OTM as my primary choices. Again, great job. Your data have confirmed my suspicions about a lot of the ammunition I have not purchased/tested and your data will be in my library :-) |
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Posted: 5/30/2017 3:30:16 PM EDT
[#22]
Good price here for Federal Fusion MSR
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SC, USA
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Posted: 5/30/2017 3:59:53 PM EDT
[#23]
Quote HistoryThanks. Lets see if the OP or anyone else has grouped this. I may just order a bunch.
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Posted: 5/30/2017 4:57:46 PM EDT
[#24]
Quote HistoryOriginally Posted By CountryGuy:
Thanks. Lets see if the OP or anyone else has grouped this. I may just order a bunch. Speer GD 64gr: 2.41 MOA Fusion MSR 62gr: 2.72 MOA A few additional for the heck of it: BH 77gr TMK: 3.07 MOA Speer 75gr GD: 1.88 MOA Speer 55gr GD: 2.87 MOA I believe (but can't confirm) that all of these group sizes would tighten up a bit on a calmer day. Nevertheless, at the ranges I would ever imagine using this gun for hunting or self defense, the group size of ANY of these 5 loads is acceptable to me. You'll have to make your own decision on that though. Molon has done a more thorough write up on Fusion vs MSR vs 62gr GD, but not from an SBR length barrel. |
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SC, USA
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Posted: 5/31/2017 7:02:27 AM EDT
[#25]
Quote HistoryOriginally Posted By Eagle_19er:
I did group all of it with this test using a Leupold Mark AR scope (3-9X40) and a lead sled but I'm not ok with calling the groupings "reliable" or the end all/be all for these rounds. I had a 3/4 value wind blowing through between 5mph and 25mph throughout the test. If you're willing to take the accuracy results for MSR and 64 GD with a HUGE grain of salt, here they are (all 10 shot groups): Speer GD 64gr: 2.41 MOA Fusion MSR 62gr: 2.72 MOA A few additional for the heck of it: BH 77gr TMK: 3.07 MOA Speer 75gr GD: 1.88 MOA Speer 55gr GD: 2.87 MOA I believe (but can't confirm) that all of these group sizes would tighten up a bit on a calmer day. Nevertheless, at the ranges I would ever imagine using this gun for hunting or self defense, the group size of ANY of these 5 loads is acceptable to me. You'll have to make your own decision on that though. Molon has done a more thorough write up on Fusion vs MSR vs 62gr GD, but not from an SBR length barrel. |
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SC, USA
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Posted: 5/31/2017 11:15:18 AM EDT
[#26]
I ran the numbers and extrapolated the best I could with the limited, non normalized data between Molon's link, Eagle_19er's current 10.5" barrel data and my 10.5" and 16" barrel data. From a non scientific standpoint since there is limited correlating data, I come to the following conclusions of 223 MSR-62 use for myself without actual MSR-62 testing in my barrels:
- For my 10.5" barrel, I believe an expanding bullet would be best at these lower velocities. MSR-62 would provide 881 # energy, GD-64 would provide 748 # energy and GD-55 would provide 834 # energy. MSR-62 bests the GD-55 by ~ 5% energy and the GD-64 is a disappointment. But I do question the MSR-62 sectioning vs. the GD 64 in the Molon post link. To my eyes, the jacket on the MSR seems to vary in thickness above the cannelure- side to side, especially towards the top while the GD-64 seems very even. Since I now question the jacket QC on the MSR-62 with this tiny sample size, I believe I will stick with the GD-55 as my primary cartridge for the 10.5" barrel and be comfortable with it for my intended uses (home, truck, UTV, ~50 - 75 yards) since I have no other data to work with at this point. - For my 16" barrel, MSR-62 would provide 970 - 1000 # energy (being generous), GD-64 would provide 978 # energy, IMI-77 OTM would provide 1274# energy, GD-75 would provide 1045 # energy, GD-55 would provide 1065# of energy and a lot of FMJ in various weights provide similar or greater energy per my data. The 223 MSR-62 seems to excel with energy in shorter barrel lengths. My 10.5" barrel and Eagle_19er's 10.5" barrel have very similar velocities for the data tested in both and knowing the data sets are not normalized. We will have to see how the MSR-62 scales in Eagle_19er's subsequent tests with longer barrel lengths so a better comparison can be made with more data. |
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Posted: 6/3/2017 12:07:55 AM EDT
[#27]
Quote HistoryOriginally Posted By CountryGuy:
Thanks. Lets see if the OP or anyone else has grouped this. I may just order a bunch. |
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Posted: 6/5/2017 4:30:34 PM EDT
[#28]
Really nicely done my man, great info. The 10.5" data was pretty revealing. I don't have a Chrono and don't plan to get one so this is really interesting info for me.
Just built a 12.5" gun for use suppressed/unsuppressed and I look forward to seeing your data on that one. Keep up the good work! |
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Posted: 6/5/2017 4:40:09 PM EDT
[#29]
Quote HistoryOriginally Posted By sevin8nin:
Really nicely done my man, great info. The 10.5" data was pretty revealing. I don't have a Chrono and don't plan to get one so this is really interesting info for me. Just built a 12.5" gun for use suppressed/unsuppressed and I look forward to seeing your data on that one. Keep up the good work! I'm looking at this Friday (June 9th) for the 11.5" and sometime next week for the for the 12.5" test. A lot of its weather dependent though. I shot the first test in 70ish degree weather and want to try to get close to that for the other barrel lengths to get the best velocity comparison. Local weather says 74 for a high on Friday with every other day around it in the 80's. |
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SC, USA
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Posted: 6/5/2017 4:43:52 PM EDT
[#30]
Quote HistoryOriginally Posted By Eagle_19er:
Thanks, people like yourself are the exact reason I'm doing it! (And of course I wondered for myself too). I'm looking at this Friday (June 9th) for the 11.5" and sometime next week for the for the 12.5" test. A lot of its weather dependent though. I shot the first test in 70ish degree weather and want to try to get close to that for the other barrel lengths to get the best velocity comparison. Local weather says 74 for a high on Friday with every other day around it in the 80's. |
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Posted: 6/8/2017 7:14:29 PM EDT
[#31]
Bump for 11.5" test completion. See 2nd post.
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SC, USA
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Posted: 6/8/2017 7:24:12 PM EDT
[#32]
I never see humidity as low as 41% except maybe in the winter :-). Another great post.
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Posted: 6/8/2017 7:37:59 PM EDT
[#33]
Quote HistoryOriginally Posted By CountryGuy:
I never see humidity as low as 41% except maybe in the winter :-). Another great post. 
It's nothing like the south though. Your hot weather/humidity is relentless...I spent a summer at Ft. Benning. |
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OK, USA
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Posted: 6/8/2017 8:11:15 PM EDT
[#34]
The 77gr TMKs actually managed to get slower? Why could that be, different chamber specs, rifling?
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Posted: 6/8/2017 8:31:14 PM EDT
[#35]
Quote HistoryOriginally Posted By doty_soty:
The 77gr TMKs actually managed to get slower? Why could that be, different chamber specs, rifling? |
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Posted: 6/8/2017 9:49:40 PM EDT
[Last Edit: bfoosh06]
[#36]
Quote HistoryOriginally Posted By Eagle_19er:
I'm honestly not sure. The Faxon 11.5" is a 1:8 barrel whereas the Noveske 10.5" is a 1:7. Both are 5.56 spec chambers. Quote HistoryOriginally Posted By Eagle_19er:
Originally Posted By doty_soty:
The 77gr TMKs actually managed to get slower? Why could that be, different chamber specs, rifling? Very good info, Thank you for your time and results ! |
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Posted: 6/8/2017 9:56:52 PM EDT
[#37]
Quote HistoryOriginally Posted By bfoosh06:
IMHO, the velocity "loss" just shows how different barrels can be. Very good info, Thank you for your time and results ! The vast majority of the rounds were faster in the 11.5" barrel, as the data shows, but that doesn't mean an anomaly can't exist. I'm interested to see how that round does in 12.5 and 14.5 barrels. |
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Posted: 6/8/2017 10:59:55 PM EDT
[Last Edit: swampvol]
[#38]
We are probably expecting around a 2-3% difference in velocity between the two barrel lengths.
That is a very narrow window and doesn't leave much room for error for a machine that the accuracy range probably isn't much less than 2-3% |
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AR, USA
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Posted: 6/9/2017 12:33:31 AM EDT
[#39]
This is interesting since some of what I read said the 11.5 leaves the 10.5 in the dust. Here it isn't a big difference. I need to look for more tests,,,
Thanks for the work,,, |
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Posted: 6/9/2017 12:51:39 AM EDT
[Last Edit: Click2Boom]
[#40]
Wow great post.
Muh ADI 69 smk stockpile lol. Looking to see if it's faster out of longer bbl The 70 tsx was scooting along compared to other heavies I was surprised wolf steel 55gr was relatively close to pmc xtac, pmc xtac 193 has quite a bit more recoil than wolf 55gr in my guns. Gonna follow this close, very interested. Thanks op! |
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Posted: 6/10/2017 10:32:36 AM EDT
[#41]
55g GD at only 9g's lighter than the 64g, yet being 300fps faster is odd.
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Posted: 6/10/2017 10:36:40 AM EDT
[#42]
Quote HistoryOriginally Posted By swampvol:
55g GD at only 9g's lighter than the 64g, yet being 300fps faster is odd. |
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Posted: 6/10/2017 10:46:45 AM EDT
[#43]
Quote HistoryOriginally Posted By Eagle_19er:
Yep, so far that's held true through both barrels and I imagine it will for the next two as well. The only explanation is that it's loaded hotter. Heavily invested in those two, but don't have any 55. May have to pick up a box from my local PSA today and try them out tomorrow. |
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SC, USA
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Posted: 6/11/2017 6:04:19 AM EDT
[#44]
Quote HistoryOriginally Posted By swampvol:
I've chronoed the 64 and 75g's out of both a 14.5 and 16", but not the 55g's. Heavily invested in those two, but don't have any 55. May have to pick up a box from my local PSA today and try them out tomorrow. |
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Posted: 6/11/2017 9:30:39 PM EDT
[Last Edit: swampvol]
[#45]
Went to PSA to pick up a box of 55 GD's to test, but they were out.
They did have a box of the MSR's that I picked up and chronoed today. They were around 90fps faster than the 64g gold dots out of my 14.5" bcm. Got an average of 2,613fps from IMI 77g Razorcore. |
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Posted: 6/11/2017 9:40:45 PM EDT
[Last Edit: Eagle_19er]
[#46]
Interesting. Maybe the 64GD uses a powder that does better in longer barrels.
I should be able to get out next weekend for the 12.5 tests, assuming the current forecast holds true. If it cools down earlier, I'll be out earlier. |
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Posted: 6/11/2017 9:44:33 PM EDT
[Last Edit: swampvol]
[#47]
Quote HistoryOriginally Posted By Eagle_19er:
Interesting. Maybe the 64GD uses a powder that does better in longer barrels. The FPS 'gap' between 64 GD and MSR did close a little from 10.5-11.5 for me. I should be able to get out next weekend for the 12.5 tests, assuming the current forecast holds true. If it cools down earlier, I'll be out earlier. Looking forward to your 12.5 and 14.5 tests. Edit to your edit: I have absolutely no clue then, which is not surprising. lol |
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SC, USA
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Posted: 6/12/2017 6:41:10 AM EDT
[Last Edit: CountryGuy]
[#48]
Quote HistoryOriginally Posted By Eagle_19er:
Interesting. Maybe the 64GD uses a powder that does better in longer barrels. I should be able to get out next weekend for the 12.5 tests, assuming the current forecast holds true. If it cools down earlier, I'll be out earlier. Velocity Energy 55 grain: 2953.1 1064.8 64 grain: 2623.6 978 75 grain: 2504.7 1044.6 My 10.5" chrome lined 1:7 Green Mountain barrel and Gold Dots: 55 grain: 2612.7 833.5 64 grain: 2293.7 747.5 75 grain: 2213.7 816 Speer's advertised data on their LE web site out of a 24" barrel 55 grain: 3220 1266 64 grain: 3000 1279 75 grain: 2775 1282 I relegated my case of 64s to storage after my chrono tests. Typically I expect a barrel length difference to be between 35 - 58 FPS/inch for most things in hand guns and .223 type things, all things else equal. I typically guesstimate at 45 - 50 FPS on avg. In general, the only significant difference I have discovered is when a faster burning pistol powder is used (favors shorter barrels) vs. a slower burning rifle or magnum pistol powder (favors longer barrels). Speer markets the 223 Gold Dots as LE... I have to think they should be using no longer than a 20" barrel for 223. |
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Posted: 6/12/2017 11:24:47 AM EDT
[#49]
Thanks for taking the time on that post @CountryGuy. Your 16" data, especially for the 64 GD, is very interesting to me. I may pick some extra boxes of select loads to test in 16" and 20" after I wrap up the SBR tests.
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Posted: 6/12/2017 6:44:26 PM EDT
[#50]
Great update, if the 62g tsx keeps putting numbers like that up, its going to force me to start buying it.. Very impressive numbers.
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