Jump to content
Brian Enos's Forums... Maku mozo!

M&P9 Pro accuracy dropped off


1911luvr

Recommended Posts

I've had a M&P Pro 5" for a couple years and have about 10K rounds through it, but I've recently started noticing some severe accuracy problems. I checked it at 50 feet and where it once shot mostly cloverleafs (I hear that was decent for a stock barrel on one of these) it now groups 4 to 5 inches or more depending on ammo.

 

I thought it might be a barrel problem so I bought a new Storm Lake 9mm barrel, but the groups are the same. I'm shooting off a rest, so I'm reasonably sure it's not me. I've tried factory ammo and several different loads I run in competition, and the performance is poor with everything. Any ideas what could be suddenly causing such poor groups?

 

 

 

Sent from my iPhone using Tapatalk

Link to comment
Share on other sites

My experience is that going from cloverleafs to 4-5" groups takes some

time, and happens slowly.  Not abrubtly.

 

No previous warnings?   Slowly increasing size of the groups?

 

I'd go back to the original ammo you used to get the cloverleafs, rather

than trying "several different loads".

 

Anything else you've changed recently?   Screws all tight?   Could the sights be slightly loose?

Link to comment
Share on other sites

My experience is that going from cloverleafs to 4-5" groups takes some

time, and happens slowly.  Not abrubtly.

 

No previous warnings?   Slowly increasing size of the groups?

 

I'd go back to the original ammo you used to get the cloverleafs, rather

than trying "several different loads".

 

Anything else you've changed recently?   Screws all tight?   Could the sights be slightly loose?


It may have been getting worse slowly, but plate racks are pretty forgiving until the groups really open up. Our club shoots a lot of steel, so I first started noticing the problem when shooting through a hole in the wall plate and on on our bowling pin plate rack at 20 yards. We don't always shoot slim plates that far so in the beginning I just thought it was me having a bad day.

As I started missing more at longer shots I decided to put it on paper and noticed the accuracy problem. I had some lead in the barrel so I thought that was the cause, and cleaned it out but only saw marginal improvement. I checked my load in another gun and it shot as well as expected, so I thought maybe the barrel was wearing and it no longer liked this load. No other loads were any better, and several were worse so I bought the new barrel thinking I damaged the crown or rifling somehow.

I shot the new barrel with my standard load and the first two shots weren't even on an 8" target at 50 feet. I checked the sights but both were tight. Once I got a round on it I kept that POA and the POI was spread out all over, up, down, left and right. I don't see anything obviously wrong with the slide, and I'm not sure how to go about checking the frame so I don't know where to go from here.


Sent from my iPhone using Tapatalk
Link to comment
Share on other sites

Call S&W and see what they say. I would maybe forget to tell them about the aftermarket barrel, probably not an issue, but why take the chance.

OTOH I'd probably pull it apart and check everything under a loupe or magnifying glass and look for rounded corners or unusual wear. Maybe around the linking block and lockup areas of the slide. It wouldn't be a terrible idea to have something to say when you call.

Sent from my Moto G (4) using Tapatalk

Link to comment
Share on other sites

My original 5" Pro bbl shot really well at the beginning, with loads it liked, but, after a while (Not sure of round count) I had the same problem. My 25 yard groups that originally were under 2", were about 5". I had a big burr at the front of the barrel hood. I was going to de-burr it, but, decided to send it to S&W. They sent it back, saying nothing was wrong, and nothing was done, but, the burr was gone, and it looked like it was removed by a blind man, using a coarse grinder. I took it to the range, and accuracy wasn't improved, so I sent it back to S&W. They called me and said it looked like somebody had been grinding on the barrel hood, and they were going to replace the barrel with a new one. I couldn't get them to admit that someone down there did the grinding. With the new barrel, accuracy still sucked. I picked up a KKM, and it will do sub 2" groups at 25 yards, but, only with Extreme 115 hp bullets. I then bought an Apex, gunsmith-fit barrel, and had a local guy that had already welded up and re-fitted a Storm lake bbl to his gun, fit it for me. So far, I've only got a couple hundred rounds of various loads through it. With 124-125 grain jhps, it really tries to shoot a 1" group, but, I always seem to get a flier, opening it up to about 2". Extreme 115 hps shoot 2" groups, BBI 160 grain coated bullets shoot 3" groups, the various 147 grain bullets all came in about 4" @ 25 yards. Xtreme 165 grain and Acme 122 grain bullets produced the worst groups. I plan to run more down it, and re-check to see if it settles in, or, gets worse.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...