[AKM]

I would like to pose a question to the experienced handloaders here. I have read in several books that flattened and cratered primers are a danger sign for pressure. But I am getting flattened and cratered primers with factory loads in my 460 Rowland. Here is a pic. The question is this. Is this really a sign of danger, or just the authors of reloading books playing it overly cautious?

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[KLN]

Your fired primers do not look out of line for a 40,000 psi pistol cartridge. Flattening and breech face marks on the primers look about right.

The cratering, or raising of the primer material around the firing pin indentation, is likely due to a loose fit of the firing pin through the breech face. Since the pistol was designed for less than 20,000 psi, careful fit of the firing pin was not a big issue. At 40,000 psi, it is. Guns designed for 40,000 generally have a more careful fit of the firing pin through the breech face, and usually a bit smoother breech face, so the pressure signs are not quite so apparent.

A stronger firing pin spring may also reduce cratering.

The high pressure .460 is pushing the 1911 quite a way, but my experience with Jim Clark is that he knows what he is doing.

Excellent photography. It sure makes it easier to discuss things with that kind of visual aid.

 

[KLN]

Clark, it is not clear what your purpose is in repeatedly posting overload data, but eventually someone is going to misunderstand it and get into trouble. I think the readership would be better served if that were kept in private between experienced reloaders who understand what the data means.

 

[Patrick Sweeney]

I too had high-pressure signs in my 460 Rowland firing factory ammo. What I found was that the full-length guide rod head was bearing against the bottom lugs of the barrel, and the pre-load was allowing the gun to unlock early.

I bevelled the top of the round boss on the guide rod head, and the "pressure signs" went away. I had run into this before when fitting a government barrel in a Commander gun, and found the lightest load giving the most horrible-looking pressure signs.

Look at your guide rod head. Is the boss circular? Are there a pair of nicks from the barrel lugs riding on it? Get out the file.

 

[AKM]

Originally posted by Patrick Sweeney:

Look at your guide rod head. Is the boss circular? Are there a pair of nicks from the barrel lugs riding on it? Get out the file.

Damn. That's a good call Patrick.

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[Patrick Sweeney]

"You can learn a lot just by watching." Yogi Berra

 

[KLN]

AKM, it will be interesting to hear your report on this development. It is not entirely clear how filing that part is going to affect your pressure signs, and it will be interesting to learn the outcome.

 

[AKM]

Originally posted by KLN:
AKM, it will be interesting to hear your report on this development. It is not entirely clear how filing that part is going to affect your pressure signs, and it will be interesting to learn the outcome.

I'm pretty interested in seeing the outcome myself. I have filed the guide rod and maybe I can get to the range tomorrow to see if it made a difference.

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[Maxthemutt]

How do you guys like your .460 Rowlands???
Thinking about buying a conversion.

 

[AKM]

I've only fired about 30rds through mine, but man, that's a hoot! How could you not love a 1911 with that kind of attitude?

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[Patrick Sweeney]

KLN, If his is like mine, the "pressure signs" will go away, and the primers will look like a normal hot load in a .45ACP.

The messy primers were an artifact of the early unlocking of the barrel, due to the pre-load the guide rod was creating.

And I definitly will pay attention to the Clark admonition about not using the 460 in certain soft pistols.