460 Rowland primer flow on starter loads

[Elkins45]

These are the results of my first testing session with my new Clark 460 Rowland conversion barrel. The gun is a Springfield Armory 1911 basic parkerized model bought in 1989. I replaced the firing pin spring with the extra power spring included in the conversion kit and used the 24 lb recoil spring.

These loads were assembled in new Starline 460 Rowland brass using WLP primers. The load was 12.0 grains of Power Pistol behind a 230 grain cast lead bullet sized to .452 and seated to a length of 1.250". The starting load for this bullet weight on Real Guns data able for 460 Rowland is actually 12.1 grains.





As I hope you can see from the photos, these starting loads show a good deal of primer flow, smearing and in a couple of case a bit of bulging. I'm a bit surprised by this because I actually used weighed charges for these test rounds and because I started slightly below the mildest listed load for this powder and bullet weight. Is this sort of primer appearance something I should just expect to experience with such a high intensity auto pistol round or should I be concerned? As you can see, there are also some extractor marks on the case heads.

Are there any 460 Rowland shooters that can give me some advice?

 

[rcmodel]

Looks to me like the hole in the breech face is much bigger then the firing pin.

Or else, it has a counter sunk firing pin hole in the breech face??

Either one is not desirable.
But it is what it is.

Winchester primers are also next to Federal, the softest primers made.
Try CCI if you can find some.

It may also be low pressure is setting the primer back and then full pressure is slamming the case back over it, slamming the FP to the rear, and re-seating the primer after the firing pin has retracted.

I'd probably keep work up to at least the starting load and see what develops.

That will really be 'It is what it is', and you will know for sure.

rc

 

[Kachok]

Call me crazy but those don't look that bad except for the one with visable leaking (which is not always due to excessive pressure) I have shot plenty of factory ammo with primers looking alot worse then that. Normally when I get primer flow the premier is flat and has lost it's rounded edge, those appear very much rounded still, darn near factory, but take that with a grain of salt I don't do nearly as much handgun as I do rifle. Another thing to remember is not all handguns are designed for the same pressure, not even close really, I would wager that normal 9mm pressure would blow a 45ACP to bits

 

[ljnowell]

Looks to me like the hole in the breech face is much bigger then the firing pin.

Or else, it has a counter sunk firing pin hole in the breech face??

Either one is not desirable.
But it is what it is.

I believe you are onto it right there RC. I dont think this is an issue with overpressure in the cartridge, but possibly the gun. These things arent a problem at the 45acp pressure level, but when getting up to the Rowland pressures they rear thier ugly head.

 

[david_r]

"These are maximum loads in my firearms and may easily be excessive in others. All loads should be reduced by 10%,"

The only other load he has on there with that combo is 12.5 gr. 12.5 gr less 10% doesn't come out to 12.1. I think you've misread his data table or maybe you didn't mean, "starting load?" I actually went and read his articles on 460 and don't see where he's suggesting a 3% difference between min and max.

What is the straight line 90 degrees off from the extractor mark? Does every case have the ejector mark on there too?

 

[Elkins45]

"These are maximum loads in my firearms and may easily be excessive in others. All loads should be reduced by 10%,"

The only other load he has on there with that combo is 12.5 gr. 12.5 gr less 10% doesn't come out to 12.1. I think you've misread his data table or maybe you didn't mean, "starting load?"

Clearly I should have read the intro paragraph rather than just assume the lowest of the two loads listed is start and the highest is max, although it does seem odd to list two different charge weights for the same bullet and then call them both maximum loads. Another (paid) source also lists 12.5 as max for this powder with a jacketed 230. Considering the lower engraving force required for cast vs jacketed, 12.0 doesn't seem like an unreasonable load.

I'll load some at 11.0 grains and then see what the primers look like. The funny thing is that with the 24lb spring this load actually failed to fully eject and cycle a couple of times, convincing me it really was a starting load.

Let this be a lesson, kids...read the whole thing before using data from ANY source.