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Posted: 7/6/2016 7:37:07 PM EDT
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OK, so if you're ever able to score some MK 319 projectiles, I figured out a good recipe.
The MK 319 is a round requested by SOCOM for use in the SCAR Heavy. It is a 130gr 7.62mm round that is barrier blind. I picked up 2,000 of these from midway for $.14 per bullet. Factory ammo is rare and pretty expensive and is made by Federal called T762TNB1. This round is optimized for short barrel 308's, specifically the Scar with a 13" barrel. The stated velocity is 2,925 from a 16" barrel and 2,750 from a 13" barrel measured at 15 feet away from muzzle. These are HOT! Using the following load, I was able to get pretty close to this with no over pressure signs. LC Brass CCI Large Rifle Primer 2.800" COAL 44.0gr Vihtavouri N133 Out of my 13" Scar a 5 shot group gave me: 2,710 2,722 2,720 2,711 2,712 
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Thanks for info. If I ever reload it I'll work up to your data. That projectile looks like a barnes ? Wonder if they make the projectiles ? No, ATK made these projectiles. OP, if only I had that Vihtavuori powder, I'd be set! I guess I need to get some now...I already have the bullets! Can you share how you worked this load up? What data did you use as a basis? |
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I am seating on the lower cannelure and crimping. This gives me the same COAL as the factory load (and the maximum COAL that will fit in a SCAR 17 mag).
I worked this load up by looking for a relatively fast powder for a 308 so there will be little flash (all powder burned in barrel). I am a fan a Vihtavouri powders for being clean burning and temp stable. Next I used Barnes info for their 130gr bullet since it was the closest thing that I could find. I figured it would be close enough to give me a fairly good starting point. Barnes manual #3 lists the Max load for the 130gr XBT at 44.5gr I started at 40.0gr and made 5 rounds, then made 5 rounds using 40.5gr, etc. I repeated in .5gr increments until 46.0gr. Next I went to the range and hooked up my magnetospeed. I started shooting and stopped when I got close to the factory stated velocity from a 13" barrel. A Scar 17 shooting these makes one hell of a squirrel gun!!! 
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Here are the MagnetoSpeed numbers out of my 13.3" SCAR 17 (cut and pinned by Nefarious arms). Crimped to bottom cannelure.
Scar 17 13" MK119 Load 46.4 Gr XBR 8028 LC 1X Case Series26 Shots:19 Min2674 Max2753 Avg2720S-D19.9 ES 79 Here are the factory numbers SeriesSCAR 17 13"Shots:10 NotesFactory MK3119. Min2694Max2766 Avg2728S-D21 ES72 I think I got pretty close to factory. |
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Here are the MagnetoSpeed numbers out of my 13.3" SCAR 17 (cut and pinned by Nefarious arms). Crimped to bottom cannelure. Scar 17 13" MK119 Load 36.4 Gr XBR 8028 LC 1X Case Series26 Shots:19 Min2674 Max2753 Avg2720S-D19.9 ES 79 Here are the factory numbers SeriesSCAR 17 13"Shots:10 NotesFactory MK3119. Min2694Max2766 Avg2728S-D21 ES72 I think I got pretty close to factory. How was the accuracy? I got XBR 8208, may have to make a note of that for down the road. |
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How was the accuracy? I got XBR 8208, may have to make a note of that for down the road. Quoted:
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Here are the MagnetoSpeed numbers out of my 13.3" SCAR 17 (cut and pinned by Nefarious arms). Crimped to bottom cannelure. Scar 17 13" MK119 Load 36.4 Gr XBR 8028 LC 1X Case Series26 Shots:19 Min2674 Max2753 Avg2720S-D19.9 ES 79 Here are the factory numbers SeriesSCAR 17 13"Shots:10 NotesFactory MK3119. Min2694Max2766 Avg2728S-D21 ES72 I think I got pretty close to factory. How was the accuracy? I got XBR 8208, may have to make a note of that for down the road. I was getting 3 MOA from factory and slightly better with my hand loads. This was with a red dot, and I have astigmatism. They're my SHTF projectiles because of their terminal ballistics. Read the Crane power point on it, it's a cool little round. |
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Here are the MagnetoSpeed numbers out of my 13.3" SCAR 17 (cut and pinned by Nefarious arms). Crimped to bottom cannelure. Scar 17 13" MK119 Load 36.4 Gr XBR 8028 LC 1X Case Series26 Shots:19 Min2674 Max2753 Avg2720S-D19.9 ES 79 Here are the factory numbers SeriesSCAR 17 13"Shots:10 NotesFactory MK3119. Min2694Max2766 Avg2728S-D21 ES72 I think I got pretty close to factory. Just curious what you pinned to make 13.3" barrel a 16"? |
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Just curious what you pinned to make 13.3" barrel a 16"? Quoted:
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Here are the MagnetoSpeed numbers out of my 13.3" SCAR 17 (cut and pinned by Nefarious arms). Crimped to bottom cannelure. Scar 17 13" MK119 Load 36.4 Gr XBR 8028 LC 1X Case Series26 Shots:19 Min2674 Max2753 Avg2720S-D19.9 ES 79 Here are the factory numbers SeriesSCAR 17 13"Shots:10 NotesFactory MK3119. Min2694Max2766 Avg2728S-D21 ES72 I think I got pretty close to factory. Just curious what you pinned to make 13.3" barrel a 16"? KAC MAMs |
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I've been using IMR XBR 8208 and NNY brass with my RRA LAR-8 with a 16" barrel.
Settled on 46.0 grains with no crimp. Loaded like the pic in the OP(seated to the front edge of the front band). Averages 2798fps with a ES of 46 and SD of 14 Also did testing at 46.5 and 47.0 (fps avg 2809 and 2855) but those loads were too hot in the NNY brass with temps that day around 75-80 degrees. I've got a bunch of BHA brass that should have more case capacity than the NNY and may try that in the future. FWIW the 45.5 load averaged 2753. Accuracy wasn't spectacular, but I wasn't expecting it either. |
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KAC MAMs Quoted:
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Here are the MagnetoSpeed numbers out of my 13.3" SCAR 17 (cut and pinned by Nefarious arms). Crimped to bottom cannelure. Scar 17 13" MK119 Load 36.4 Gr XBR 8028 LC 1X Case Series26 Shots:19 Min2674 Max2753 Avg2720S-D19.9 ES 79 Here are the factory numbers SeriesSCAR 17 13"Shots:10 NotesFactory MK3119. Min2694Max2766 Avg2728S-D21 ES72 I think I got pretty close to factory. Just curious what you pinned to make 13.3" barrel a 16"? KAC MAMs 
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KAC MAMs Quoted:
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Here are the MagnetoSpeed numbers out of my 13.3" SCAR 17 (cut and pinned by Nefarious arms). Crimped to bottom cannelure. Scar 17 13" MK119 Load 36.4 Gr XBR 8028 LC 1X Case Series26 Shots:19 Min2674 Max2753 Avg2720S-D19.9 ES 79 Here are the factory numbers SeriesSCAR 17 13"Shots:10 NotesFactory MK3119. Min2694Max2766 Avg2728S-D21 ES72 I think I got pretty close to factory. Just curious what you pinned to make 13.3" barrel a 16"? KAC MAMs Had no idea those where that long... |
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Quoted: Had no idea those where that long... Quoted: Quoted: Quoted: Quoted: Here are the MagnetoSpeed numbers out of my 13.3" SCAR 17 (cut and pinned by Nefarious arms). Crimped to bottom cannelure. Scar 17 13" MK119 Load 36.4 Gr XBR 8028 LC 1X Case Series26 Shots:19 Min2674 Max2753 Avg2720S-D19.9 ES 79 Here are the factory numbers SeriesSCAR 17 13"Shots:10 NotesFactory MK3119. Min2694Max2766 Avg2728S-D21 ES72 I think I got pretty close to factory. Just curious what you pinned to make 13.3" barrel a 16"? KAC MAMs Had no idea those where that long... <snip> this is a technical forum not GD. dryflash3 |
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Had no idea those where that long... Quoted:
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Here are the MagnetoSpeed numbers out of my 13.3" SCAR 17 (cut and pinned by Nefarious arms). Crimped to bottom cannelure. Scar 17 13" MK119 Load 36.4 Gr XBR 8028 LC 1X Case Series26 Shots:19 Min2674 Max2753 Avg2720S-D19.9 ES 79 Here are the factory numbers SeriesSCAR 17 13"Shots:10 NotesFactory MK3119. Min2694Max2766 Avg2728S-D21 ES72 I think I got pretty close to factory. Just curious what you pinned to make 13.3" barrel a 16"? KAC MAMs Had no idea those where that long... Marvin Pitts at Nefarious Arms is the only person I'd trust pinning a $400 muzzle brake. I believe the length includes the flash prongs. The gen 1 prongs are a tick longer. |
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I have purchased 200 of the Mk319 projectiles but I have a question.
In this post I see 36.4 grains of XBR 8208 used- [Jump To Reply]Quoted:
Here are the MagnetoSpeed numbers out of my 13.3" SCAR 17 (cut and pinned by Nefarious arms). Crimped to bottom cannelure. Scar 17 13" MK119 Load 36.4 Gr XBR 8028 LC 1X Case Series26 Shots:19 Min2674 Max2753 Avg2720S-D19.9 ES 79 Here are the factory numbers SeriesSCAR 17 13"Shots:10 NotesFactory MK3119. Min2694Max2766 Avg2728S-D21 ES72 I think I got pretty close to factory. In this post I see 46 grains of XBR 8208 being used I've been using IMR XBR 8208 and NNY brass with my RRA LAR-8 with a 16" barrel.
Settled on 46.0 grains with no crimp. Loaded like the pic in the OP(seated to the front edge of the front band). Averages 2798fps with a ES of 46 and SD of 14 Also did testing at 46.5 and 47.0 (fps avg 2809 and 2855) but those loads were too hot in the NNY brass with temps that day around 75-80 degrees. I've got a bunch of BHA brass that should have more case capacity than the NNY and may try that in the future. FWIW the 45.5 load averaged 2753. Accuracy wasn't spectacular, but I wasn't expecting it either. This seems like a very extreme spread on powder usage for similar velocities out of very different barrel lengths. |
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