Crimping Rifle Rounds

[jelenko]

Just FYI. Many [ I think most] highpower competitors do not crimp.
Crimp/not crimp is an age old question in highpower.
There's several discussions from the past about it on the National Match Competition forum on US Rifle Teams site.
You do have to register to view the threads.

 

[Cfshooter]

Even worse, someone turned me loose with a ziz wheel on a dremel. Looks like a 100% Bubba job, but it worked so well, I never tried to make another one done properly.

I do love my Dremel too!

 

[Cfshooter]

Just FYI. Many [ I think most] highpower competitors do not crimp.
Crimp/not crimp is an age old question in highpower.
There's several discussions from the past about it on the National Match Competition forum on US Rifle Teams site.
You do have to register to view the threads.

Thank you for that, I will go and check it out. I have never crimped before (well I did crimp 10 rounds years ago to see if there was any difference in accuracy for a load, there wasn't), but also never checked setback on rounds loaded that long and being driven into chamber by a BCG. Mag length rounds didn't have any real noticeable setback. If the entire neck was in contact with bearing surface of bullet, all was good.

 

[jelenko]

Thank you for that, I will go and check it out. I have never crimped before (well I did crimp 10 rounds years ago to see if there was any difference in accuracy for a load, there wasn't), but also never checked setback on rounds loaded that long and being driven into chamber by a BCG. Mag length rounds didn't have any real noticeable setback. If the entire neck was in contact with bearing surface of bullet, all was good.

For long line loads [where the bullet is loaded longer than the mag], I'm reasonably certain that almost [maybe none] no one crimps.
There is a suspicion that crimping could have a negative affect on accuracy. => you might want to retest accuracy of crimped vs non crimped rounds that are loaded long.
You mentioned that in the test you did, crimping produced 1/3 MOA smaller groups. Can you say what the actual sizes of the groups were?

Also, I think most highpower rounds are loaded with 3-4 thousandths neck tension - but I'm less sure about that.

 

[Cfshooter]

For long line loads [where the bullet is loaded longer than the mag], I'm reasonably certain that almost [maybe none] no one crimps.
There is a suspicion that crimping could have a negative affect on accuracy. => you might want to retest accuracy of crimped vs non crimped rounds that are loaded long.
You mentioned that in the test you did, crimping produced 1/3 MOA smaller groups. Can you say what the actual sizes of the groups were?

Also, I think most highpower rounds are loaded with 3-4 thousandths neck tension - but I'm less sure about that.

Measuring them, it wasn’t 1/3, crimped averaged .88 moa, not crimped 1.11 moa. I will develop this load using light crimp and see how it does for fun. For future long loads in AR, I will just increase neck tension.