Smith and Wesson MP 9mm with comp shooting high

[pc13]

Equipment:

Smith and Wesson MP 9mm Core with Delta Point Reflex

Carver Comp with KKM 9mm Barrel

Carver striker spring

12 lb recoil spring

Apex Flat Faced Trigger

Problem: Today I shot it at 15 yards, 3 rounds at one target and they were all high about 6-8 inches. I tried different ammo (reloads) they all shot high.

I took off the Carver Comp, KKM barrel and put back in factory 15lb recoil spring and it was spot on with my reloads. I have order a 13 lb spring from speed shooters, but it hasn't arrived yet.

I want to keep the Carver Comp, but it does not shoot accurately. Can anyone tell me why after it's installed why am I shooting high. I am holding the same sight picture. I tired bench with gun on table, bench with only elbows touching table and standing away from the bench and all high on target. I am using Iron sights at this point and again it is dead on with Factory Barrel and Factory recoil spring. Iron sights at this point and they are not adjustable from Smith and Wesson.

Why does it shoot high and what can be done to fix this? different recoil spring. or is it the lock up with the KKM Barrel? tnks in advance

[Hi-Power Jack]

I'd be surprised if springs caused this difference in POI.

I would guess it's more because of the lockup or fitting of

the two different barrels. (Not a final answer from an

expert, just a guess - let's see how the experts line up).

That doesn't mean that the new barrel is not accurate -

just that it has a different POI - it might be more accurate

(group size).

To test accuracy, I'd back it up to 20-25 yards, firmly bench

rest it and fire larger group sizes. Then look at group size,

not POI.

If I'm correct, you'd need to adjust your sights if you're going

to use the KKM/Carver - you'll probably want to put on a

dot sight of some type, e.g. C-More. That should make

all this problem go away quickly.

Good luck with it.

[peterthefish]

OP states he's using a dot sight. Hat aside, I agree that different POI <> inaccurate. If it groups well, you'll need to adjust the sight to zero it with the new barrel / comp. My RMR has hash marks on the adjustment screws - I scratched a Zero mark on them, and take a pic of where they are at zero on each gun. I can change it between guns and get it close enough to zero without firing a shot for most shooting.

It takes only a very minor change in

[bmiller]

My M&P is very finicky. You change anything and it throws off the point of impact. 115 gr bullets shoot about 12" lower than my 147 gr at 25 yards. I think it is because some guns unlock so fast. I put a home made comp on mine and it shoots about 3' low at 25 yards. It is a relatively accurate pistol, but anything you do to it knocks off poi. I think there are things that could be done to it to change that but it will take some serious tinkering. I am learning towards developing a combo that works and sticking to it.

[drysideshooter]

I would be tempted to chrono the same load through each barrel. If they are hitting high with the barrel/comp but straight above the POI of the other barrel, it could be a simple matter of velocity.

It really shouldn't be a surprise that changing barrels changes the POI.

[Hi-Power Jack]

It shouldn't be a surprise that changing barrels changes the POI.

Well said. +1.

[BeerBaron]

Part of the point of a compensator is that it pulls forward which increases the lock time. Assuming it's doing that job then it's easy to understand why poi has changed. To be honest even just changing barrels of be surprised if poi didn't change at least a little. The only solution is an adjustable sight of some kind.