Home Forums Hunting & Shooting Handguns Anyone do a .460 Rowland conversion?

No Sir, but easily ran 230gr FMJ-FP's to 1200 fps in an all steel 1911 five inch with Starline Super brass and Longshot, quiet the little handful, 'Smith sprung it all for Super for me, Bud was so impressed he kept piling hundred dollar bills on top of my Trane A/C unit till he left with it all ; ]

The only reservation I'd have about ACP in the Rowland is depending on the extractor for headspacing, but people do it all the time.

The extractor holds the shorter cartridge in place. 45 ACP in the Rowland works the same way as firing 40 S&W in a 10mm

Yep, it feeds from the mag like a CRF rifle, with the extractor taking control as soon as the round clears the mag. I just don't like to stress the extractor like that or depend on it for proper headspacing, though it will work fine if the extractor is of proper dimensions. Pressure in a .45 ACP is probably low enough that case stretch is not a concern.

A lot of people are firing 40s in 10mms and I'm not hearing of mass failures.

Yes, and both are a bad idea in a 1911. You can get away with it in a Glock with no issues, not so in a 1911.

This is what happens with the 40 S&W when it jumps in front of the extractor (which occasionally can/does happen).

That looks like it went a couple K past SAAMI max...

Looks like it, but not at all; it was a mild load with a milder than normal report and velocity. That picture is what happens when headspace is equal to the depth of the extractor; the case slams back past the extractor into the breech face. Not something I'd recommend doing on a regular basis.

The 1911 firing pin is long enough to light off a cartridge in that position. A Glock won't fire at all in that condition.

The only way to prevent that in a 1911 when using shorter brass than the chamber is to seat bullets out far enough to prevent it from happening. Not possible to do with all bullets, but works with some.

So the case is coming back at a damn good speed and then hits the breech face. That would tend to distort things.

Yes exactly. It's an exaggerated version of the common "pressure signs" people see in rifles as well, that are often due to headspace. In this case, headspace can be measured in fractions of an inch rather than thousandths. Try measuring case head expansion on a case that does this...

Notice the missing chunk of rim too where the extractor was - that wasn't ripped off from extraction, it was sheared off in the other direction when the case slammed back past the extractor.

Here's something interesting, turned out to be a too-light firing pin allowing extrusion of the primer into FP hole then being sheared when the barrel unlocked. Ruger SR1911 running .45 super with 20-lb recoil spring, 28-lb mainspring, and Flat FPS.

Changing to a Wilson(?) bulletproof made things good. Ruger fp was 32 or so grains, replacement was about 90. The extra-strength fp spring didn't help.


Left side casings were in question.

To light or undersized? Pretty sure both Wilson and EGW offer larger sized firing pins to reduce/eliminate blanking.

Paul

I can see how that might happen, with hotter loads anyway. The other solution I'd have considered would be thicker primer cups if that was an option, depending what you were already using.

If the pressure of the load is high enough that it's trying to flatten out the dimple the firing pin made in the primer, and the firing pin light enough to be pushed back (the firing pin normally remains against the primer through the peak pressure moment of firing), you could experience that issue. A heavier firing pin could potentially fix it, as you did, or thicker/stiffer primer cups could resist the pressure better.

A similar issue that's common with some pistols is shearing of the primer face from early unlocking. The barrel drops downward in the slide when it unlocks, and if that happens while there is still significant pressure on the round (and the primer is pressed against the firing pin hole by that pressure) then the area immediately around the primer indent can be sheared off. This is more common in light weight slides, and was a common complaint about the Sig 365 when it came out. The smaller Glock models can do this as well with hotter loads..

Too light, pin mic'ed correct diameter but weighed about a third.



Next step would have been bushing it for a smaller diameter pin.