Xtreme 147 gr in .357--any problems?

[rutilate]

Is there a problem either in the short or long term in shooting .357 diameter bullets in my M&P 9?

I started reloading my favorite 9mm recipe of 3.4gr Titegroup behind 147gr X-treme bullets at 1.145 COAL and completed ~1600 rounds and realized that the latest batch of bullets was .357 and not the .356 that I normally use. Doh! Apparently I made a mistake in ordering. That's a lot of bullets to pull!

I'm worried about higher pressure with the Titegroup, and longer term, eroding the barrel so as to prevent me from shooting .356 anytime hereafter.

I very carefully measured the muzzle with calipers and found it to be .356" groove to groove. I don't know if this barrel is tapered from breach to muzzle. I've just moved and don't have any of my fishing tackle to use in slugging the bore but can get some if necessary.

I shot 10 rounds and took pictures of the primers. As you can see there is a slight embossing into the firing pin recess that is ever so slightly more well-defined than my other ammo, but there is no squaring-off of the primer cup shoulders.

Am I right in the assessment that I'm probably ok with pressure? What about the long-term effect?

[chuck s]

That is all I shoot, as do most of my friends. We find them more accurate than the .356 bullets. I can drop the charge .1 gr (using WST) and get the same velocity. They will not hurt your barrel or gun.

[dauntedfuture]

You are fine. I have shot .357 jacket bullets in a 9mm barrel. Plated and lead bullets are commonly .356 and it does not take much for them to be .357. In reality a plated bullet loads more like a lead bullet then it does like a jacketed bullet. Sierra used to make, and might still make a .309 diameter match bullet for use in worn .308 match rifles.

[OPENB]

I believe Schueman recommended .357 bullets in his .355 barrels. Thought I read that here.

[rutilate]

Thanks for weighing in, folks. These are producing slightly higher pressure than normal as evidenced by the slight debossing of the primers. Do you envision there being any difficulties in shooting from my SIG P938 or should I save these for my M&P 9?

[cjim]

Thanks for weighing in, folks. These are producing slightly higher pressure than normal as evidenced by the slight debossing of the primers. Do you envision there being any difficulties in shooting from my SIG P938 or should I save these for my M&P 9?

Probably be a tad snappier in the 938 with the smaller frame & bbl.