NavyShooter
CGN Ultra frequent flyer
- Location
- XMU Local .303
I think the real concern when dealing with a semi-auto is the possibility that the round would be moved within the neck of the case when it is slammed up the feed ramp and shoved into the chamber.
I remember a while back (like, several years) doing a test to see what affect on LOA this might have.
I dummy loaded 50 rounds, numbered each of them(25 crimped, 25 non-crimped), and cycled them through my AR-15. Afterwards, I picked up each round and measured them for LOA and compared them to the previous result.
After the first cycle, no change to any round's LOA.
After 2 cycles through, no round had changed LOA.
After the 3rd cycle, I believe 2 or 4 of the non-crimped rounds showed a .001" decrease in LOA. (Length Over All)
None of the crimped rounds showed any decrease in LOA.
So, my decision was not to bother with worrying about crimping too much, as it was not a significant concern for LOA.
Now, that said, and in hindsight, and if I had the tool, a seated bullet runout test would be the better thing to check.
IE, load up 25 rounds, crimp. Load up 25 rounds, no crimp.
Measure each bullet's LOA, and runout, number each round as you do so.
Cycle each dummy round through the action, and each time, test the LOA and runout.
If I had a seated bullet runout tester, I'd probably try that test, just to put this to rest in my own mind.
Anyone have one I can borrow? Results will be posted public domain here to share?
NS
I remember a while back (like, several years) doing a test to see what affect on LOA this might have.
I dummy loaded 50 rounds, numbered each of them(25 crimped, 25 non-crimped), and cycled them through my AR-15. Afterwards, I picked up each round and measured them for LOA and compared them to the previous result.
After the first cycle, no change to any round's LOA.
After 2 cycles through, no round had changed LOA.
After the 3rd cycle, I believe 2 or 4 of the non-crimped rounds showed a .001" decrease in LOA. (Length Over All)
None of the crimped rounds showed any decrease in LOA.
So, my decision was not to bother with worrying about crimping too much, as it was not a significant concern for LOA.
Now, that said, and in hindsight, and if I had the tool, a seated bullet runout test would be the better thing to check.
IE, load up 25 rounds, crimp. Load up 25 rounds, no crimp.
Measure each bullet's LOA, and runout, number each round as you do so.
Cycle each dummy round through the action, and each time, test the LOA and runout.
If I had a seated bullet runout tester, I'd probably try that test, just to put this to rest in my own mind.
Anyone have one I can borrow? Results will be posted public domain here to share?
NS
