Load evaluation

[Slidelock]

I've just purchased a custom Glock 24 from S _ J Customs and am having trouble developing a load for it from a bagged rest. I was told by them that often polymer pistols do not shoot well from a sandbag and that I should steady my wrists only on the sandbags. I do have minor familial hand tremors and need a better way to steady the gun. A friend of mine suggested resting the gun on the magwell on a padded surface. I tried it and it seems quite steady. The groups improved a little but not much. This is such an easy technique that I just keep thinking there has got to be something wrong with it otherwise I would have read about using it to develop loads in other pistol types, i.e. single stacks, hi-caps, etc. Can you comment on this technique and/or suggest something else I might try? Thanks.

[calishootr]

some semi-auto's arnt 'happy' when resting on a mag, because usually the mag is being pressed up too far into the gun causing feed problems, when pickup and held 'normally' the problems go away...

as for improving the groups, that depends on a number of things, for me, the first thing that comes off of a Glock is their factory sights, groups(for me) improve drastically, the load??? it may not be 'the one' for the gun at this point??? have someone else shoot it and see what happens, bottom line, the guns will pretty much always out-shoot their human owners, with your tremors you may have to plug in a certain amount of fudge factor in the group size

[Jman]

http://www.brianenos.com/forums/index.php?showtopic=117545&st=0&p=1331768entry1331768

[grayguns]

Hi! There are some considerations when shooting off of a bench or any other surface. In my experience, a bench / bag / barricade can each lend stability, but also induce some variability in recoil resistance that can potentially affect relative POI due to the physics of barrel time and unlocking rate, and corresponding effects on the relative line of departure of the bullet. Changes in the resistance presented by the frame assembly will affect poi for a given shot in some roughly inverse relation to the weight of the frame, all else equal. Thus, a Glock will theoretically show more displacement on the target from variations in how it's supported than, say, a 56-ounce Bianchi Cup gun firing the same load. Similarly, resting the pistol butt or magazine on the bench can yield a POI change; that resistance changes as the magazine is depleted, adding another variable that can have some additive effect. Indeed, I've seen this many times in training and testing. These effects on POI are roughly analagous to what we expect when we change bullet weights and velocities. In each case, we're changing the relative line of bullet departure to it's starting point, and thus to the sights.

There are also other factors affecting relative POI changes due to changes in support. Higher bore axis will enhance POI displacement, as will barrel length, lockup values and so forth. In any event, please realize that, as long as you bag or bench consistently and are rolling off clean trigger breaks while holding a properly aligned sight picture, most pistols will still print groups reasonably representative of the gun/load combination's capability, albeit perhaps to a different POI. I believe the reason why some folks say that a given pistol shoots poorly when fired off a bag or bench has more to do with a lack of consistency in the method used, and not as much the method itself.

And finally, the difference in POI from bags, bench or wrist support is generally not so great. For example, the SIG Pro 9mm I normally carry on duty will shoot 2.5" left and high with standard-pressure 147's versus +p 115's at 25 meters. This is perhaps an extreme example, however. This pistol also prints a bit lower off a bag than offhand at distance. On the other hand, in the '90's I had a well-fitted, rather heavy 5" 1911 9mm I built to shoot Stock category at the Biachi Cup with that always shot about to the same place with a wide variety of loads and shooting positions.

So, I'd focus on developing a highly consistent bench technique that doesn't place loads on the slide and frame if possible, and from which you can press off good breaks while seeing clear alignment. If after this, your gun/load combo still isn't giving you acceptable groups, it might be time to evaluate you load.

Most all barrels will shoot with at least one or two loads; the trick is finding it. I hope this helps and wish you luck!

-Bruce