AR-15 enhanced firing pin?

Talk about the AR15 style rifles chambered in 450 Bushmaster.

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AR-15 enhanced firing pin?

Postby PJames » Sun Jan 01, 2017 12:19 am

I reloaded a few test rounds from 38 to 40 grains of W296 and a 250gr FP berry bullet CCI mag primers. I had no hang fires and very low soot on the 40gr load. I used the factory crip to .456 didn't chrono or shoot for groups just wanted to see if it went bang. But, I started to think would an enhance firing pin possibly eliminate any chance of a hang fire or help to ensure a good primer strike?
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Re: AR-15 enhanced firing pin?

Postby Hoot » Sun Jan 01, 2017 9:15 am

PJames wrote:I reloaded a few test rounds from 38 to 40 grains of W296 and a 250gr FP berry bullet CCI mag primers. I had no hang fires and very low soot on the 40gr load. I used the factory crip to .456 didn't chrono or shoot for groups just wanted to see if it went bang. But, I started to think would an enhance firing pin possibly eliminate any chance of a hang fire or help to ensure a good primer strike?


Was that a typo when you said .456, meaning .476? I would imagine that would squeeze them down to the point of affecting accuracy. Maybe not. How did they group? Its been a long time since I've shot a Berry's bullet, but back when I did, they may have been copper electro-plated, but they were still soft like bare lead, just shiny. The plating came off on a few shots, one piece embedding into the display of my chrony! I was not fatal, more of a shot across the bow and the last time I used Berry's bullets.

I once reported that experience in a forum where a Berry's rep was participating and got called out on it because according to him, my experience was because the 230 fmj I had the experience with was "not designed for rifle velocities." He claimed they also made rifle qualified, electro-plated bullets (assumed thicker plating) and my experience would have bee different if I had used them. That was a while ago and perhaps before they had .452 rifle qualified bullets. Never went back to them to find out.

I just paused this reply to quickly google that bullet you used. While it is designed for the faster 45 LC velocity as opposed to 45 ACP, the Berry Website says they are rated for a max velocity of only 1250fps. Caveat Emptor. :|

I've been using brass Rem 7 1/2 primers since day 2 of reloading for this caliber and I've never seen an imprinted primer to the degree that I worried about a slam fire. IE barely visible on the rare occasion when it happens.

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Re: AR-15 enhanced firing pin?

Postby PJames » Sun Jan 01, 2017 10:19 am

Typo Yes, .476 sorry about that. The berry bullets grouped ok at 30 yards had several touching but, I was not shooting for groups maybe next time. They seemed ok for plinking no sign of bullets going sideways nice round holes.
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Re: AR-15 enhanced firing pin?

Postby Hoot » Sun Jan 01, 2017 11:32 am

PJames wrote:Typo Yes, .476 sorry about that. The berry bullets grouped ok at 30 yards had several touching but, I was not shooting for groups maybe next time. They seemed ok for plinking no sign of bullets going sideways nice round holes.


Well, the proof is in the pudding. We banter a lot about 100 yd groups even though the lethality of this caliber is such that you don't need 1 MOA performance unless you're pushing them out to 250 yds and beyond. Geometry doesn't lie. Doesn't have an agenda. Doesn't represent a monetary interest. It clean and antiseptic. It also says that POI over POA errors increase the further the path of travel gets. A 3 inch group at 100 yds is something like a 10 inch group at 300 yds and that's not even factoring in wind that can be blowing at different velocities and possibly directions along the way.

So resultant groups, while mostly relevant to the shooter's hunting needs, are at least a predictor to how a load may perform at a range over what the original shooter's needs were. The accuracy which produces a 10 inch group at 300 yds, produces one ragged hole of less than an inch diameter at 30 yds. Not suggesting you were content with that performance distance. As you implied, it was to test reliability and repeatability.

So, aside from verifying reliable cycling and ignition, we all don't have a lot of choices for quality metrics other than groups, hence the interest in them.

In this fat caliber, the price we pay for making weight with solid, lead cored bullets is them being shorter, sometimes significantly so, than their hollow point or all copper equivalents. That may leave more capacity for powder, but in a mouth headspaced caliber, it poses a challenge to getting a crimp that holds the bullet in one spot during the inertial effects of chambering and the lesser effect of recoil down in the magazine. Thicker walled cup and core bullets will resist deformation more than thin walled, plated bullets. The result of that is a tighter pinch when the case mouth is compressed down upon them. Think trying to hold into a water balloon vs a grapefruit of the same size. The resistance to deformation is important as is the memory of the medium. Squeeze an egg of Silly Putty and then just the Silly Putty itself. One springs back, one doesn't. The shell matters.

Its warmed up to +24 in the sun, so time to do my Sunday preventive maintenance down at the club rifle range.

Happy New Year everyone.

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