Storm Lake M&P Barrel

[Severian]

So I was disappointed with the size of the groups I was getting with my 9mm M&P pro this Summer and Fall. I replaced the stock barrel with one from Storm Lake. The groups tightened up a bit, but not a great deal--from 4" at 25yrds to 3" of so. One disappointment with the SL barrel is that it's finicky about OAL. The stock barrel will eat just about anything, even rounds that are loaded out to 1.170 and don't drop cleanly into the case guage. The longer rounds may bind up in the magazine, but they will cycle through the stock barrel with no problems. The SL barrel, however, does not like anything over 1.110 and will jam up badly if you use a round that is slightly difficult to drop into the (Dillon) 9mm case gauge. It's a bit frustrating. I'm not sure if it's worth the little bit of extra accurady I get from it.

Anyone else have a similar experience?

[kend]

If the round will barely go into the case gauge and then it sticks in the barrel it means the chamber is a little tighter than the gauge, exactly the reason I use the barrel out of the gun for a gauge. The gauges are made to accept SAAMI spec ammo and match barrels have tighter chambers.

[mcracco]

Zactly; use your barrel as the gauge and seat the bullet xx" off lands. I use .020" as a reasonable number. I have 2 SL barrels and never had a problem with OAL using that method.

But I am a bit confused as you say you have difficulty dropping a round in a Dillon gauge. Is this a diameter/crimp issue or an OAL issue?

[Severian]

Zactly; use your barrel as the gauge and seat the bullet xx" off lands. I use .020" as a reasonable number. I have 2 SL barrels and never had a problem with OAL using that method.

But I am a bit confused as you say you have difficulty dropping a round in a Dillon gauge. Is this a diameter/crimp issue or an OAL issue?

Well, you know how some used brass is not always true to size. Sometimes they are expanded because of being fired from other guns (Glock barrels, etc.). Sometimes the rim of the brass gets marred from some other gun's extractor. Stuff like that. The brass has to be pretty dang perfect to work in my SL barrel. Thanks for the information! I can use my Dillon guage as long as I remember to accept no bullet that is the least bit tight.

[mcracco]

Geez, I don't know. I've been shooting mixed brass for quite a while now. The only I notice is some of the military stuff sizes harder but once that is done everything is true and it chambers no problem.

[9X23Guy]

I run a SL barrel in my M&P Pro with no issue but there are a few reasons for that. Accuracy is far better than stock, I get much better than 3" with mine but this has many variables such as the level of the shooter, the trigger, etc. Lets keep in mind it's also a semi-drop in barrel, not hand fitted. I also have done a trigger job to mine. I load 124 JHP MG at 1.15 OAL. I don't believe there to be a lot of variation barrel to barrel. Their technical support was great and they have been doing barrels for the M&P the longest. You can always have a smith throat the barrel a little too. As far as not chambering Glock brass you need to look into a Lee Factory Crimp Die. I shoot mixed head stamp brass from whatever gun. The factory crimp die not only puts a crimp IF you want one it sizes the case where it is needed. Most of my cases get a little rub around the bullet and towards the base of the round after this last step. I have 4,000 rounds through my M&P with one malfunction. After putting in the SL barrel I had a round that didn't go all the way into battery and that was in the first hundred rounds. After that, smooth sailing. Good luck.

[Revopop]

I run a SL barrel in my M&P Pro with no issue but there are a few reasons for that. Accuracy is far better than stock, I get much better than 3" with mine but this has many variables such as the level of the shooter, the trigger, etc. Lets keep in mind it's also a semi-drop in barrel, not hand fitted. I also have done a trigger job to mine. I load 124 JHP MG at 1.15 OAL. I don't believe there to be a lot of variation barrel to barrel. Their technical support was great and they have been doing barrels for the M&P the longest. You can always have a smith throat the barrel a little too. As far as not chambering Glock brass you need to look into a Lee Factory Crimp Die. I shoot mixed head stamp brass from whatever gun. The factory crimp die not only puts a crimp IF you want one it sizes the case where it is needed. Most of my cases get a little rub around the bullet and towards the base of the round after this last step. I have 4,000 rounds through my M&P with one malfunction. After putting in the SL barrel I had a round that didn't go all the way into battery and that was in the first hundred rounds. After that, smooth sailing. Good luck.

I used to have the same problem with a Wilson KZ45 when I'd first started out reloading using a Lee hand press. The factory crimp die fixed all my problems. Of course, upgrading to a Dillon press fixed a lot of problems too!