Shooting M&P for Accuracy off Bench

[470nitro]

I did some searching and saw reference to some very good info here and there about people's experience with shooting an M&P for accuracy off a bench and figured it might make good discussion material in its own thread.

My 9 Pro has been historically pretty inconsistent accuracy-wise sandbagged off a bench (bag beneath the dustcover and under the mag basepad). My better 5-8 shot groups were in the 3" - 4" range at 20 yards. I did all my load development this way.

Then I read a post from G-Man Bart from March of this year about how he shoots over a rolled up towel to support his wrists and takes a more firm, solid grip than he has to with other pistols.

So I tried this yesterday and WOW. I guess my pistol needed that. The same load that was consistently 3"-4" now dropped to between 1.6" and 2.2" 8 shot groups at the same distance. I rest my wrists atop a bag and make sure the pistol is touching nothing but my hands take a tight grip (tighter than I do with my STI).

Now, I'm questioning all my past testing when coming up with a load.

So my question is: What has been your experience? With your pistol, does it make a difference? If some of you have seen what I have above, does anyone have a conclusion or even an educated guess as to why some guns may not like direct sandbag contact/support? I'm guessing it may have to do with the lockup/unlock of the barrel but I really don't know.

[mrwhite1]

Dave, are you still supporting the front area under the dustcover while you are doing this?

If you take a rest off the bottom of the gun, the magazine could over inserting or be raising ammo slightly higher than normal, thereby putting slightly more upward pressure on slide. Im not certain if / how that may affect accuracy?

It seems to me that keeping the grip (Magazine base) off the ground and supported more with your hand would be the best option. That way you wouldnt put any additional stress on anything but the receiver under dust cover area.

Edited August 12, 2010 by mrwhite1

[JeffWard]

I changed front sights on my Pro Series (Dawson). I first shot the gun off a bag (under the dustcover), and my groups were 3-4" high at 20yards. DAMN... THEN, I shot the gun offhand at 20 yards, and my hits were right at POA (top of the front sight).

Same sight picture... but bizarre. I'm not sure how resting the gun on the dustcover would move POI by 3-4"!!!!

When I went to a rolled up towel under my wrists, gun unsupported, I got tighter groups at POA/POI.

I won't shoot my M&P of sandbags again (under the dust-cover)

Jeff

[want2race]

I'll have to look at the M&P again, but could the dust cover be contacting the slide with enough downward pressure? Glocks can do this. If that's the case, It's similar to resting a rifle barrel instead of FF HG on a rest. Right?

I haven't grouped mine off a rest. Standing freestyle yes, sandbag no. My groups are similar to your results while resting your wrists and not the gun.

[470nitro]

MrWhite: No, that was one of the big changes was having nothing under the dustcover. Now there is nothing touching the gun (under mag basepad or under dustcover) but my hands.

Jeff: Glad to see that you had tried both also. I'm of the same opinion at the moment (not rest on anything again). I found my groups were tightest when I took a very firm grip with my hands (probably more than when I'm shooting a match).

Shaun: Not sure but when you take a look at one, please let me know. I'm away for the weekend and can't look at my M&P now. Good to know your groups are in the same neighborhood.

Edited August 12, 2010 by 470nitro

[G-ManBart]

Every so often I run into something like this that makes me just shake my head. The rolled up towel, very firm grip works, but I'm not sure why.

I've only toyed with it a little bit, but it seems to work with Glocks as well. Two days ago I worked a qualification day and one of the other instructors asked me to check a Glock for zero. At 25yds I tried a supported barricade position that was very stable and got hits an inch or two right. Then I tried prone with the mag resting on the grass. The groups were centered, but high. Finally, I took a cardboard target (only thing close by) folded it up and used it to support my wrists while prone with a firm grip....centered hits for both elevation and windage...like a 2" group. If I loosened up a little bit on my grip, the POI was an inch or two high. I then got up and put the last two shots into the supported wrist/firm grip 2" group offhand. I'm no expert on polymer guns, but in my limited testing with this idead so far, they seem to be a bit more sensitive when it comes to rests, grip pressure etc. R,

[want2race]

Just looked at the 9Pro. The dust cover does flex. If you were to really wrench down on the bench rest, you could very well get the dust cover to move the slide.

Shooting 1911's I always seem to get the best groups the tighter I hold it and the firmer I press it down into the rest. I've also wondered if a stronger recoil spring would effect accuracy (for the better).

[paul gilman]

I am one of the old guys and when I am testing for accuracy I support my forearms and wrist or shoot from a old position called roll over prone. I find that if the gun is not supported in any way other than your hands it is more accurate.

When you are shooting for accuracy from roll over prone you move your support hand around for elevation, I have found this to work better with a hand gun for accuracy then shooting from a bench.I am old and fat so this is not my favorite position.

Also I find that Glocks and M&P's just don't seem to shoot as well as other firearms for me.

[latech15]

I shot a friends m&p 9 pro last night. He told me that he was shooting consistently 3" low and 2" right at 20 yards. I shot WWB 115 gr and Magtech 147gr. The WWB groups were much more open than the Magtech. From a rest, dust cover on a sandbag and elbows on table the groups were right on evelation wise and consistently 2" right. Shooting the WWB freehand at 20 yards the group was right on.

I don't think that the sandbag under the dust cover and nothing else touching impacted the elevation what-so-ever in my test. I also think that since I am used to a much lighter trigger, that I might have been pushing the trigger a little bit to the left accounting for the windage change going from bagged to freehand. I suggested he move the rear sight a bit to account for the windage and work on his trigger technique. He is a revolver shooter and is probably getting on the trigger a bit to hard from being used to a much heavier pull (accounting for the low hits).