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Posted: 12/9/2018 2:03:12 PM EDT
[Last Edit: Blain][Edited]
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5.56 M193 Velocity Shoot Off Part II:
View Part 1 HERE!!! 
After my initial test results, I wanted to purchase some more South African and Independence M193 as those two were the clear winners of the M193 "shoot out". I received some batches of South African M193 that had different lot numbers on them than the lot I initially tested. I was curious if there was much of a difference between the different lots. For those who will critique the difference in the chronograph distances between the tests (3 vs. 4 yards), the actual differences in velocity are actually negligible. For those interested in calculating actually muzzle velocity, from all velocities measured according to Federal's Ballistics calculator, https://www.federalpremium.com/ballistics-calculator, the actual muzzle velocity should be ~ + 10 fps from velocities recorded from 9 feet (3 yrds) I'd also like to mention that temperature does play a large role in bullet velocities. As many know, hotter temperatures will effect the gunpowder in a way that leads to higher pressures and velocities. That's why it's generally not a good idea to work up hot handloads in the winter and then use those same loads in summer, you may get over pressure issues. The general rule of thumb is you gain / loose ~1 fps velocity for every ~1 degree F in temperature change. IE, the results I got at 50 degree temperature would be roughly 25 fps higher at 75 degrees and roughly 25 fps lower at 35 degrees. Therefore I think that ~ 50 degrees is a good baseline for testing, as many people will experience actual environment extremes of up to +/- 50 degrees from the 50 degree mark. Heck, in my part of the country, we experience that type of temperature extreme every year from winter to summer! Information on the barrels tested: 18” CHF Barrel: This is an FN M249 barrel blank 1-7 twist barrel with the “machine gun steel” and “double thick chrome lining”. Bought from Riflegear.com, had the gas port opened up to ~.102 and has roughly 2,500 – 3,000 rounds through it, which is nothing for a M249 barrel. According to an FN engineer when I called them, it is more so the unique proprietary composition of the M249 barrel steel itself that contributes to the super long life rather than the CHF process. The “double thick” chrome lining, is also a different type of chrome plating that plates thicker than the mil spec on the M4. It is not just the M4 chrome lining applied twice as thick. 18.5” CHF Barrel: Barrel was a FN M249 1-7 twist barrel blank same as the above 18” but was originally a 20” FN CHF purchased from PSA and cut down to 18.5”. Why 18.5”? For two reasons. One, it still allows use of a bayonet (where as the 18” requires an extended flash hider for the same) and two it allows for more dwell time / gas port pressure without having to open up the gas port. Since my 18” is modified to allow attachment of a bayonet with the extended flash hider, it is actually the same length as the 18.5” barrel w/ standard A2, so might as well have more barrel length than flash hider length. This barrel also has around 2,000 – 3,000 rounds through it, which again is nothing for this barrel. 20” Mckay Enterprises A1 Profile Barrel: Last time I tested a 20” barrel from an as new Colt AR15A4 rifle as a control. This time I wanted to test a different 20” barrel. The one I ended up choosing was a Mckay Enterprises 20” A1 Profile replacement barrel that I had built up as a modern A1 style KISS rifle on a C7 upper. It is A1 profile in all dimensions, chrome lined, and 1-7 rifling twist so can use all modern ammunition. This barrel has around 500 rounds through it and is in as new condition. Details on the Testing: The testing was broken up into 2 days, the temperature on the first day was around 50 degrees F. I only shot three strings with the CHF 18” barrel on day one from one of the different lots of South African M193. I also shot a string of the “pre nerfed” Federal XM193 from 2016 that I had good results with last test. The discrepancies in results I found from the first lot of South African I tested caused me to come back for the second day and do another extensive round of velocity testing (hence this post, Part II). Testing Part II: Day 1: Conducted November 4th 2018 ~ 4pm. Temperature ~50 degrees Distance from Chrony 9 ft / 3 yrds Testing Part II Day 2: Conducted November 11th 2018 ~ 1pm. Temperature ~40 degrees Distance from Chrony 9 ft / 3 yrds Guide: H = Highest velocity of a string. L = Lowest velocity of a string. Avg = The mean of all shots fired in a string. ES = Extreme spread in a string. SD = Standard Deviation of a string (calculated by the chrony Testing Part II: Day 1: South African M193 PMP Year: ?? 20xx Lot # 165 (Packaged in 50 round boxes, in 200 round plastic “battle packs”, 5 packs per .50 cal metal ammo can) 18” CHF 1. 3,215 2. 3,148 L 3. 3,188 4. 3,148 5. 3,165 6. 3,173 7. 3,253 H 8. 3,232 9. 3,151 10. 3,224 AVG: 3,190 fps ES: 105 SD: 38.5 18” CHF Bonus Round (shot another string on the first day with the same lot) 1. 3,193 2. 3,217 3. 3,180 4. 3,119 L 5. 3,199 6. 3,210 7. 3,210 8. 3,157 9. 3,224 H 10. (ran out of ammo from my box as I hit the range first) AVG: 3,190 fps ES: 106 SD: 35 Total Average: 3,190 fps - for both 10 round strings (20 Rounds) Federal XM193 2016 Lot # SMQ16J815-290 (Packaged loose in 150 round boxes) Same lot as in Test Part 1 18” CHF 1. 3,171 2. 3,136 L 3. 3,210 4. 3,232 5. 3,198 6. 3,211 7. 3,220 8. 3,220 9. 3,229 10. 3,254 H AVG: 3,208 fps ES:117 SD: 33.5 *** -15 FPS difference from 18" Average in Testing Part 1 Testing Part II Day 2: Conducted November 11th 2018 ~ 1pm. Temperature ~40 degrees Distance from Chrony 9 ft / 3 yrds South African M193 PMP NF Year: ?? 20xx Lot # 165 (Packaged in 50 round boxes, in 200 round plastic “battle packs”, 5 packs per .50 cal metal ammo can) 18” CHF 1. 3,115 L 2. 3,148 3. 3,133 4. 3,123 5. 3,153 6. 3,158 7. 3,196 8. 3,116 9. 3,172 10. 3,198 H AVG: 3,151 fps ES: 84 SD: 30.5 18” CHF Bonus Round (shot another string at the end of all testing) 1. 3,183 2. 3,162 3. 3,159 4. 3,275 H 5. 3,160 6. 3,213 7. 3,204 8. 3,136 L 9. 3,140 10. 3,159 AVG: 3,179 fps ES: 140 SD: 42 Total Average: 3,165 fps - for both 10 round strings (20 Rounds) 25 FPS less than Day 1 18.5” CHF 1. 3,189 2. 3,235 3. 3,195 4. 3,235 H 5. 3,153 L 6. 3,215 7. 3,188 8. 3,161 9. 3,198 10. 3,177 AVG: 3,195 fps ES: 82 SD: 28 (difference from 18” 30 fps) 20” Mckay Enterprises 1. 3,194 L 2. 3,194 3. 3,221 4. 3,196 5. 3,239 6. 3,242 7. 3,267 8. 3,291 9. 3,215 10. 3,265 AVG: 3,232 fps ES: 96.5 SD: 34 (difference from 18.5” 37 fps) South African M193 PMP NF Year: ?? 20xx Lot # 198 (Packaged in 50 round boxes, in 200 round plastic “battle packs”, 5 packs per .50 cal metal ammo can) 18” CHF 1. 3,162 L 2. 3,214 3. 3,221 H 4. 3,197 5. 3,199 6. 3,210 7. 3,198 8. 3,219 9. 3,210 10. 3,193 AVG: 3,202 fps ES: 56 SD: 17 18” CHF Bonus Round (shot another string at the end of all testing) 1. 3,279 H 2. 3,193 3. 3,238 4. 3,253 5. 3,217 6. 3,188 L 7. 3,249 8. 3,209 9. 3,198 10. 3,214 AVG: 3,224 fps ES: 91.5 SD: 30 Total Average: 3,213 fps - for both 10 round strings (20 Rounds) 18.5” CHF 1. 3,247 2. 3,281 3. 3,241 4. 3,220 5. 3,257 6. 3,236 7. 3,210 L 8. 3,296 H 9. 3,248 10. 3,253 AVG: 3,249 fps ES: 86.5 SD: 25.5 (difference from 18” 36 fps) 20” Mckay Enterprises 1. 3,263 2. 3,259 3. 3,310 4. 3,280 5. 3,245 L 6. 3,279 7. 3,249 8. 3,372 H 9. 3,331 10. 3,247 AVG: 3,283 fps ES: 127.5 SD: 42 (difference from 18.5” 34 fps) South African M193 PMP NF Year: ?? 20xx Lot # 195, Same Lot as in Test Part 1 (Packaged in 50 round boxes, in 200 round plastic “battle packs”, 5 packs per .50 cal metal ammo can) 18” CHF 1. 3,220 2. 3,220 3. 3,240 4. 3,198 L 5. 3,241 6. 3,254 7. 3,317 H 8. 3,288 9. 3,200 10. 3,268 AVG: 3,245 fps ES: 118 SD: 38 *** -5 FPS difference than 18" Total Average from Testing Part 1 18.5” CHF 1. 3,234 2. 3,203 L 3. 3,259 4. 3,261 5. 3,288 6. 3,285 7. 3,313 H 8. 3,290 9. 3,312 10. 3,273 AVG: 3,272 fps ES: 110.5 SD: 34 (difference from 18” 27 fps) *** +7 FPS difference from 18.5" Average in Testing Part 1 20” Mckay Enterprises 1. 3,316 2. 3,303 3. 3,292 4. 3,349 H 5. 3,275 L 6. 3,310 7. 3,345 8. 3,331 9. 3,317 10. 3,324 AVG: 3,316 fps ES: 74 SD: 23 (difference from 18.5” 44 fps) Federal XM193 2017 Lot # SMQ17C815-334 (Packaged on Stripper Clips) Same lot as in Test Part 1 18” CHF 1. 3,214 2. 3,275 H 3. 3,253 4. 3,188 5. 3,210 6. 3,222 7. 3,217 8. 3,201 9. 3,179 10. 3,164 L AVG: 3,212 fps ES: 110 SD: 33 *** +33 FPS difference from 18" Total Average in Testing Part 1 18.5” CHF 1. 3,226 2. 3,235 3. 3,233 4. 3,230 5. 3,210 L 6. 3,239 7. 3,233 8. 3,240 H 9. 3,221 10. 3,230 AVG: 3,230 fps ES: 30 SD: 9 (difference from 18” 18 fps) *** +20 FPS difference from 18.5" Average in Testing Part 1 20” Mckay Enterprises 1. 3,281 L 2. 3,296 3. 3,310 4. 3,290 5. 3,298 6. 3,333 7. 3,286 8. 3,307 9. 3,283 10. 3,354 H AVG: 3,304 fps ES: 73 SD: 24 (difference from 18.5” 74 fps) Independence XM193 2017 Lot # FC17C001-183 (Packaged in 20 round boxes, 25 boxes per .50 cal metal ammo can) – Same Lot as in Test Part 1 18” CHF 1. 3,158 2. 3,153 3. 3,159 4. 3,184 5. 3,193 6. 3,181 7. 3,203 H 8. 3,127 L 9. 3,166 10. 3,193 AVG: 3,172 fps ES: 76 SD: 23 *** -56 FPS difference from 18" Total Average in Testing Part 1 18.5” CHF 1. 3,214 L 2. 3,274 3. 3,283 4. 3,336 H 5. 3,323 6. 3,216 7. 3,260 8. 3,290 9. 3,268 10. (Ran out of ammo) AVG: 3,274 fps ES: 122 SD: 41.5 (difference from 18” total 102 fps) *** +8 FPS difference from 18.5" Average in Testing Part 1 20” Mckay Enterprises 1. 3,366 H 2. 3,341 3. 3,362 4. 3,317 5. 3,345 6. 3,304 7. 3,354 8. 3,341 9. 3,294 L 10. 3,323 H AVG: 3,335 fps ES: 71.5 SD: 24 (difference from 18.5” 61 fps) Independence XM193 2015 Lot # FC16A001-162 (Packaged in 20 round boxes) 18” CHF 1. 3,231 2. 3,261 3. 3,296 4. 3,243 5. 3,232 6. 3,254 7. 3,230 L 8. 3,310 H AVG: 3,257 fps ES: 80.5 SD: 30.5 20” Mckay Enterprises 1. 3,353 2. 3,374 3. 3,322 4. 3,307 L 5. 3,386 6. 3,394 H (Only had one box to test between the 2 barrels, got some non-readings) AVG: 3,356 fps ES: 87 SD: 35 (difference from 18.5” 61 fps) Observations: Very surprisingly, the barrel on the Mckay Enterprises 20” A1 profile barrel seems to have much higher velocities than the Colt AR15A4 20” barrel, and I suspect other 20” barrels as well. This is one of the cases where a 20” barrel makes a big difference from an 18”, though the 18.5” is still close velocity wise. Though, I am not sure if that is just a case of this particular barrel being faster and an outliner. If the barrel was cut down to 18”, I suspect we would see higher velocities than the FN CHF 18” barrel just because I believe it to be a “faster barrel” for whatever reason. By chance, or by design? Who knows. Still some very high velocities across the board despite it being somewhat cold out (almost 15 degrees colder). I wonder how much of that is due to the powders tested being temperature insensitive, or the rounds themselves just being very hot? I'd be interested to retest these barrels and loads at a higher summer temperature, say 80 agrees. Though I'd trust any round that demonstrates such high performance at only 40 degrees. Surprising that the different lots of South African M193 had such different velocity results, especially comparing the lowest (165) to the highest (195). Lot #165 also seems a lot more inconsistent. The South African 195 lot continued to perform at a very high level, even at the ~ 15 degree lower temperature. The flattened ball powder they use seems to be fairly temperature insensitive. Again, high velocity results from Independence, though for some reason the more recent 2017 doesn't seem to agree with my 18” barrel. The older 2015 lot was even faster and more consistent across all of he barrel lengths. Both lots of the older “pre nerfed” Federal XM193 continued to performed very well (2017 stripper clip loaded lot and 2016 150 box loose packed lot). .......STAY TUNED FOR PART III (16" Barrel Results)!!!!!! Check out Part III (16" Barrel Results) HERE!!! |
Put down the Optic! Learn how to shoot the REAL way!
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https://www.youtube.com/watch?v=ligUEAJH25E
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https://www.youtube.com/watch?v=ligUEAJH25E
| Thank you. I absolutely did not mind seeing those results. That's ideally what I like to see from M193 so I was very impressed. Especially considering it was 40 degrees out, so you know it would perform at least as well at higher temperatures. The performance from the Mckay barrel was unexpected to say the least! More than impressive! |
Put down the Optic! Learn how to shoot the REAL way!
***************************************
https://www.youtube.com/watch?v=ligUEAJH25E
***************************************
https://www.youtube.com/watch?v=ligUEAJH25E
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