PA10 accuracy

[mley1]

Yesterday I went to Primary Arms near where I live and got an JP extractor for my bolt. Fixed the bolt. Went shooting today. Did some load work. Shot some factory rounds and had some decent groups. I shot a few 1.5" groups. I had a ten shot group that shot into 1.5". I had a ton of 3 shot groups that were touching, but always added a couple more shots to open them up a touch. Right now, the rifle is a solid 1.5" rifle with several types of ammo. I'm planning on doing some reloading to get those groups sub moa. At least that's my goal. The groups today weren't too bad. Sure was a pretty day for shooting too.

On the reloads I haven't been crimping the bullets. A buddy of mine tells me that perhaps I should crimp. He thinks that the fliers on the reloads may be due to the bullets slightly moving when the bolt slams them home into the chamber. What do ya'll think?

[98Z5V]

2 hours ago, mley1 said:

On the reloads I haven't been crimping the bullets. A buddy of mine tells me that perhaps I should crimp. He thinks that the fliers on the reloads may be due to the bullets slightly moving when the bolt slams them home into the chamber. What do ya'll think?

What I've learned over the years - crimp semi-auto loads. 

I can tell you I've personally seen this - as well as others here that were at the range when this happened.  We were possibly saved by a failure to feed, in a 5.56 gun running a Beta 100rd drum.  None of the reloads were crimped.  The setback (into the case) was so severe, just from recoil on a bump stock, that a setback round locked up the feeding operation.  Had it NOT locked it up, and actually chambered, that spike in chamber pressure, from compacting that round like it did, could have been disastrous.

Looking at every other round we could see, down into that Beta mag - they were all setback... 

So, don't crimp your bolt-gun rounds - cool. Got it. 

You need to crimp anything that's gonna go through a semi. 

Edited March 2, 2018 by 98Z5V

[mley1]

Roger that. I’ve got a crimping die on the way. 

[Sisco]

3 hours ago, mley1 said:

Roger that. I’ve got a crimping die on the way. 

I even have some Lake City 5.56 reloads I had to run through the crimping die because I was getting set backs with them.

[Hotwrench]

I still have to wonder if a cannelure isn't a good idea because it makes it clearer, quicker if setback is becoming a problem. Just a glance let's you know. I know we have been over this in the past and I am not talking about high accuracy rounds for target only use but more practical use rounds.

[mley1]

I haven't noticed any setback in any of the factory rounds I've fired. The reloads I've been developing have only been shot one at a time, as I'm trying to develop a good accuracy load with the TTSX bullets. My plan is to use my reloads for hunting. So, I definitely want them reliable, without the possibility of any set back. When I hunt, I don't normally use mags with more than ten in capacity. In fact, I've found the 20-30 round mags in both my .308 and 5.56 are a pain to move around inside a blind. The mags also get in the way when shooting from a bench at the range. So, I've purchased ten round mags for those purposes. About the only time I've used the 30's was on some hog and coyote hunts where my shooting was more open, standing and sitting, with no bench or window from a blind.

I'm using RCBS full length, small base, resizing dies. The TTSX bullets do have cannelures. They're smooth, not ridged like some bullets have. So, I think they'd be easy to crimp. Right now, my seating depth puts the case rim right in the middle of the top cannelure. Off hand I don't remember the OAL, but the rounds just fit into the magazine with no binding and operate smoothly. From what I'm reading the TTSX bullets do good with a jump to the lands, more so than other bullets. I can believe this, as the factory Barnes TTSX loads were getting decent accuracy out of my rifle, and they're seated a few thousandths deeper than mine.

[98Z5V]

55 minutes ago, mley1 said:

I haven't noticed any setback in any of the factory rounds I've fired. The reloads I've been developing have only been shot one at a time, as I'm trying to develop a good accuracy load with the TTSX bullets. My plan is to use my reloads for hunting. So, I definitely want them reliable, without the possibility of any set back.

Once you find your final recipe for accuracy, make sure you retest the load with the crimp on there, and see if it's still performing like you want - crimping will change the neck tension slightly, and neck tension does affect accuracy.

[bfoosh006]

Any day shooting is a good day.
Those are good groups from factory ammo.

Uniform neck tension is important to accuracy... so I'd crimp just enough to prevent possible setback... pushing the crimped bullet into a solid surface will show you if there is enough crimp / neck tension... if it doesn't budge.. you should have enough.

Edited March 3, 2018 by bfoosh006