Latest 223 Wylde Build

[HKGuns]

I don't. Carbon deposited on exposed threads after firing 35 rounds is negligible. I shoot the rifle before attaching a flash hider, then compare groups to those fired after the flash hider is installed. It's something I started doing after I saw tight groups at 300 yards with a post ban match barrel sans flash hider back in the 1990's. 10 shots per group is my standard. I shoot 5 warm up rounds, then 3 separate 10 shot groups with a warm barrel at 300 yards. The average group size is entered in my rifle log and the process with flash hider attached gets repeated every 2,500 rounds on a match rifle.

When attaching a flash hider to a match barrel, I apply blue Loctite and screw the flash hider on finger tight. If consistent sub 3/4 MOA groups are not necessary, I attach the flash hider using a peel washer and torque to 10 Ft. Lbs. A witness mark is scribed on the flash hider underneath the barrel and it gets checked frequently.

John Holliger sells good barrels. Yours should shoot.

Thanks.

[T2C]

If you were firing your favorite ammunition through the same length barrel with a 5.56mm chamber, you may see an increase in velocity when firing it through your new barrel with .223 Wylde chamber. That may account for a difference in accuracy.

For example, I chronographed M193 55g FMJ with L.C. headstamps through a Colt HBAR built in 1993. The rifle could pass for new; it's hardly been fired. The 20" barrel is marked 5.56mm and Average Velocity is 3,138 fps. I shot a 4-3/4" group with it at 300 yards this morning.

The same ammunition chronographs at 3,247 fps out of a 20" barrel with .223 Wylde chamber. That's an increase of 109 fps and the groups open up to 7-1/4" at 300 yards.

Keep at it, you should be able to figure it out.

[HKGuns]

Finally was able to get it to group today.

I loaded 3 (77gr SMK) rounds of XBR and TAC at each charge weight in .3gr increments. If it won’t shoot three well it won’t shoot 5 well.

I found two charge weights in XBR that shoot equal to or less than .5 MOA and one weight in the TAC test.

I now have options and can experiment with less than mag length seating depth to see if that changes anything.

77gr SMK - Mag length - 24.0 gr TAC



77gr SMK - Mag length - 22.3 gr XBR



WARNING: Please do NOT duplicate these loads as they may not be safe in your rifle.

[HKGuns]

If you were firing your favorite ammunition through the same length barrel with a 5.56mm chamber, you may see an increase in velocity when firing it through your new barrel with .223 Wylde chamber. That may account for a difference in accuracy.

I think this is exactly what was going on…..Thanks.

After shooting the test groups above I took that same favorite load to the 200 yard range and they were all over the place. (Because it is what I had in quantity.)

More testing is needed before I settle on a load for this rifle.

[HKGuns]

I found an LE6920 upper I forgot about lying in my safe.

Counting this as a build since I installed the MI hand guard, milled, drilled and Cerakoted the lower.

Colt 6920 barrel and upper (factory shaved FSB)
Midwest Industries 2 piece MLOK rail

Defense Distributed 80% Lower
Sionics LPK / Enhanced Trigger
Complete VLTOR A5 rear end
Magpul CTR stock
Radian Raptor CH
HK Battle Grip
Leupold VX R Patrol 1.25 - 4x [pulled and repurposed from one of my HK MR556 rifles that is getting new glass and hand guard.]