Reloading for 600 and 1000 yards

[rickOshay]

SCR: are you shooting your loads "round robin"? Or do you shoot all 5 of one load then move to the next? By shooting round robin you normalize some of the barrel heat and fouling issues.

[LR1955]

I am going to load at least 20-rounds of each load and 6-fouling rounds. That should tell the tale. Also, I am guilty of expecting one ragged hole, bench rest results. It seems like plenty of other Grendel guys are getting that kind of accuracy. I guess I am too obsessive....LOL

SCR:

Most guys here are not shooting enough ammo to get a statistically strong result. So, take with a grain of salt the 'one ragged hole' groups. My bet is that there are probably nine groups that aren't 'one ragged hole', if they even shot that many in one or two sessions.

Dry the barrel and shoot two or three shots to fowl (if you think it is needed), then shoot your strings.

If a shot goes to your call, nothing is wrong with the load, rifle, sight, etc. It went precisely where your eyes told you it would go. It may not be in your group but it went where you expected it to go so don't blame the rifle, ammo, bullet, etc. That's the problem with using raw measure to figure out accuracy potential. Unless you have the rifle locked into a shooting vice and pull the trigger via mechanical means, a human will always induce some sort of error into the shot.

If you can't call shots well enough, you can shoot ten and throw out the farthest shot away from the center of your group. Or you can keep the group. It is really up to you based on your standards.

Since you have already prejudiced yourself on one of those loads, you may need to run a blind test. I am sure you can figure out a way to run such a test and it would certainly give you a better result because you wouldn't know when shooting which load you were using. It would require a bit more time and more targets but it would also give you a result without prejudice. I have run such tests myself and the results have normally been very surprising to me.

LR1955

[LRRPF52]

[quote=surfcityred]Thanks so much for all of the replies to my thread. I will attempt to answer all of your questions and perhaps ask a few more.


LRRPF52: I purchased this 24" Grendel upper complete from Accuracy Systems in Colorado. You mention "lapping my bolt to the extension". How is that done? Are there any instructions or videos on line? Regarding the Grendel Reloading Handbook, I do not have one. I have been getting most of my info on line from various forum sources and powder manufacturer tables. I actually called Accuracy Systems and asked who manufactured their barrel but they refused to tell me.

QUOTE]

I would like some info on lapping bolts to the extension as well.

Lapping the bolt to the extension involves taking a sized piece of brass, cutting it in-half radially, then placing a stiff spring inside the two halves of the case.

You then remove the extractor and ejector on your bolt, place liberal amounts of lapping compound on the backs of the lugs, install the bolt with cam pin and firing pin + retainer into the carrier, assemble the BCG into the upper, close the receivers, and cycle the action by hand repeatedly until the lugs and lapping compound work into the bearing surfaces of the barrel extension teeth.

This balances out the lug contact, so that you don't have uneven stress on the critical pressured components of the system, and helps with accuracy. The technique comes from blue-printing and truing of custom-built rifle actions, and transferred over to the AR15 with competitive shooters.