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y5e06
10th October 2011, 12:49
I recently picked a new RIA 9mm Mid-Size with GI accoutrements from CenterFireSystems. Iíve put a few hundred rounds through it so far and seem to be afflicted by vertical stringing and perhaps a barrel fit issue.
Iíve read many different posts in regards to barrel fit. Iíve done a lot of the checks suggested. The oneís result I find myself concerned with is when checking the barrel hood vertical play in the slide while in battery. I set up a dial indicator to measure this and get 0.008Ē-0.009Ē or so play. If I gently push down on the hood I get no play. If I press a tad harder I get a movement down of about 0.005Ē. If I press hard it drops to 0.008Ē total with no further movement. The slide does move rearward at the same time in what seems to indicate it is camming down along the lower lugs. Visual inspection of the link does not appear as if it is riding the link or standing on the link in lock-up.
checking the wear pattern I see thin wear marks where the lower lug horizontal surfaces rides the slide stop, which I would think is a good thing. However the very bottom 1/2 of the tips of the lugs are shiny as if they are taking part of the impact/wear.
A few of the posts I read indicate this isnít a huge deal but will affect accuracy with vertical stringing. Well, whaddya know Iím experiencing some pretty decent stringing. So, with the type of stringing Iím seeing, does this jive with the amount of barrel play Iíve measured?
These groups were shot at 10yrds off hand. Based on the layout of the range I didnít really have the means to shoot from a rest. This particular pic is one where Winchester White Box 115gr FMJ was used. I have others using Monarch 115gr FMJ (Academy Sports reboxed Barnaul I think), I get the same results using a few other combinations including 147gr Power Pistol handloads my friend had. Often the first shot from a freshly inserted mag is the lowest, the rest end up near the bullseye and a few filling in the stringing in between.
I know shooterís error could certainly be a factor in these groups, but Iíve been shooting a number of other pistols with narry a hint of the same groups, including a pair of smith revolvers, kahr 9mm, glock 40, buckmark .22 and maybe one or two others.
On top of all this, the gun exhibits very bad nose-dive and jamming when using various HP ammo but no problems with FJM RN (no surprise). I only have the one factory issued Check-Mate mag.
Opinions on this matter? Is this something that would warrant return to Advanced Tactical for fixing? I got this piece with plans of throwing 5,000 if not 10,000 rounds down the barrel, so longevity and precision (ah, hemÖ accuracy) is a concern. And, yes, I realize this is a budget mass production gun. So that is what I need determine, if something of this nature should be sent in for fixing. Excluding the stringing issue, would you still have the same opinion?
Other individual posts in regards to similar discussions
http://forum.m1911.org/showpost.php?p=137850&postcount=6

http://forum.m1911.org/showpost.php?p=233859&postcount=6

http://forum.m1911.org/showpost.php?p=122012&postcount=7

I did measure vertical lug engagement and got 0.045Ē- 0.046Ē so that seems good. But, these measurements are without/before any barrel drop when pressing down on the hood. Also the paper tear test gives me about 0.006Ē clearance between the hood and the breech face in lockup for endplay. Timing also seemed to checkout versus the Timing Test in the technical section. When at the range I checked out 5 different 1911's at the counter and none of them had any perceptible barrel movement.

In battery:
http://im1.shutterfly.com/procsrserv/47a1ce31b3127cce98548ac805b200000030100AbuHLJk2Zt2 PA/cwvDm9asA3Lw9atmAbl5etGTDg

Pressing down on barrel:
http://im1.shutterfly.com/procsrserv/47a1ce31b3127cce98548ac9848300000030100AbuHLJk2Zt2 PA/cwvDm9asA3Lw9atmAbl5etGTDg

sample Target, worst case. Not all look this bad:
http://im1.shutterfly.com/procsrserv/47a1ce31b3127cce98548ab605cc00000030100AbuHLJk2Zt2 PA/cwvDm9asA3Lw9atmAbl5etGTDg

Hawkmoon
10th October 2011, 12:51
If you can push down of the barrel, it MUST be riding the link.

However, virtually all production 1911s do so, and the military issue ones did as well.

niemi24s
10th October 2011, 19:51
On the assumption your gun is built to Army Ordnance Government Model specifications, the vertical play at the aft end of the barrel will be in the vicinity of 0.010" or a bit less on the average gun. That play is due to the built-in slop in the link system from the barrel through the link to the frame. It must be measured from with the barrel levered upward at its aft end to the barrel pushed down at its aft end. And if the slide is the reference point, that measurement must be made with the slide fully down on the frame, otherwise the 0.004" of vertical play between the slide and frame on the average Gov't Model gets involved.

Another factor to consider is the 0.010" of play between the muzzle and slide in the average government model. Taken together, these can (assuming the barrel can be at either extreme when fired) result in vertical stringing of a bit more than 4" at 25yds.

And the hood of an in-spec Government Model 1911 can never touch the breechface. Your gun does not seem to be out of spec for a Government Model. If you want a tack-driver, a fitted barrel & bushing are in order.

Regards

Rick McC.
11th October 2011, 09:50
Your best (least costly) alternative would be to get a custom bushing made to to your specs (frame ID, barrel OD) by EGW.

Take care,

Rick

Lazarus
11th October 2011, 10:10
Interestingly, across the board vertical stringing reports turn out to be heavily weighted toward the shooter, rather than the equipment. In this case you have correctly noted that there is some movement in the bushing and in the barrel lockup. As niemi said, that's got to account for some inacuracy but not vertical stringing per se. The first and most effective improvement will be a well fitted bushing (not tight, just not sloppy). Remember to avoid barrel springing when fitting. Then if you still aren't satisfied, (since it looks like you already have some nice tools at hand), replace the barrel.

Lazarus

11 Bravo
11th October 2011, 12:13
Isn't the OP's pistol a bushing-less design? I'm not sure how one might tighten up the cone-shaped barrel to slide fit. If there is a problem the solution may be to contact the warranty repair department and see if they can provide you with a better fitting barrel/slide combo.

y5e06
11th October 2011, 23:59
all, thanks for the replys. sounds like every thing is in spec given the nature of a GI type piece. As mentioned, this is a bushingless system. i'm learning my way through the basic principles of 1911 function and smithing so fitting a new barrel is beyond my skillset at the moment... but maybe down the line. thats the plan anyway. i need to pickup some tools and books shortly. there is a wealth of info on this sight just in the old posts. Thanks

stans
12th October 2011, 05:03
With a bushingless barrel, the only thing you can do is improve lock up at the rear. Sometimes links have really generous tolerances and a fitted, match link might remove some of the play. Otherwise, a fitted barrel should take care of any slop.

Other things to consider:
Diameter and concentricity of the bore and rifling.
Consistency of the ammunition
Shooter's ability to put the sights at the same place every time and control the trigger.

Hawkmoon
12th October 2011, 10:40
Before tearing into the gun, I would both shoot it off a rest, and have another good shooter or three try it. I know you indicated that your range isn't set up for a rest, but that doesn't sound right. Any range can accommodate some kind of rest. I've shot off a .50 caliber ammo can from the prone position at an outdoor range, and I've used a variety of ad hoc items for a rest at the indoor range before I bought a dedicated pistol rest.