Yet again I've learned something while running an event. Forgive me if this is old news...
For the record, I do not own nor have I ever shot an M&P 15-22. I am stating this from observation & feedback from an experienced shooter on my line this past weekend.
With the exception of some sort of buffer inside the fore-grip, the barrel is free floating. Also pretty much the entire 15-22 is constructed of plastic/composite material.
Well, if one were to sling-up with this rifle with any kind of appreciable tension, the downward & perhaps lateral pressure exerted on the fore-grip/rails will flex this composite material enough to pull the sights out of alignment with the barrel.
I've heard this can happen with ARs, but with these little plastic rifles, the effects can be pretty dramatic. The shooter on my line ended up ditching the sling altogether & his shooting did improve.
I suppose it would be possible to work with this, but you'd have to be able to duplicate pretty much the exact amount & direction of tension on the sling to compensate for it.
Anyway, just thought i'd throw that out there for awareness/discussion.
mal
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I am not an expert on such things, so bear with this description please. My son's 10/22 is in a Tapco stock which looks much like the M&P (and other "tactical" stocks). Teh top rail screws into the bottom rail, which is where the sling attaches. With the intent of limiting this sort of deflection, we have removed the top rail (which clamped down solidly onto the barrel). Now, in theory, the bottom rail might deflect from sling tension but the barrel will remain in place. Does that sound logical? (Does it make any sense at all?)
Trust me, it is not a real life issue that can effect 4 MOA accuracy. I have thousands of rounds through my 15-22 and have used it with both beefy adults and unkind kids.
It will produce more than enough accuracy and the sling's not gonna toss your rounds. I have arms that are large and I like to go serious on the tension. I have seen no real world shift due to going super tight on the sling tension.
The 15-22 is a great rifle and tons of fun. It is not perfect, but is excellent. There are accessories that can add fun to it, but none that are needed to beat an AQT and that is great!
(http://farm5.staticflickr.com/4052/4642042195_f3ccbbba80_z.jpg)
If a person is really worried, the end cap pops right off. I removed the one on my 15/22 just in case it might matter.
I fired a M&P 15-22 on several ocassions last year with a sling and found a huge change in point of impact as sling tension or positions changed. The rifle was very sensititive to sling pressure. While zeroing prone on squares, I switched to a sitting position for practice, and the change in position/sling tension didn't even put my rounds back on the square. An IIT I was working with struggled zeroing their MP 15-22 as well, and ditched the sling altogether, as did I when shooting one.
Man, you guys make this thing sound like its made out of aluminum foil, now I don't know, I can only speculate because I don't have any personal experence firing this partular platform, but especially with a free float upper I cannot imagine being able to put enough pressure on it to bend the barrle in the slightest, unless you fired so many rounds so fast though it that you made the barrle red hot. Now with the hand guards being plastic I can see where you may some way torque that but and if you have you sights on the hand guard that may effect poa-poi. I have see them on the firing line quite a bit, they seem to be a solid rifle, and everyon that owns one swears by them. So it may be an equipment error but from the limited experience and from personal testamonys that I have Heard I would be hard pressed to blam it on the rifle.
The entire receiver is plastic. We've seen it here, too, usually with, ahem, larger shooters. It's not the barrel that bends, it's the receiver itself. I've seen kids and women use a sling on the M&P22 with no issues, but I've seen several big guys have problems with it. We had one shooter who couldn't crack 210 - he finally got rid of the sling entirely, and proceeded to post a 236 with his M&P15-22.
Shot a 226 with iron sights using one today. My sling was not snug, it was tight. More rounds downrange with your rifle, the more you learn it. My worthless .02
In the case MAL speaks of, I was the shooter that day.
Even with the forearm/barrel spacer removed, my particular M&P 15-22 strings the group unmercifully under sling pressure. I doubt it's a sight issue, as it does it equally with the original sights or a receiver mounted Eotech.
I managed to shoot 210 without a sling, a testament to the basic accuracy of the 15-22.
I have tried the sling mount in various positions on the bottom rail, and can see that moving the sling mount point rearward does move the string upwards. Still, the group moves enough under sling pressure to drop it right off the target. Say, roughly 6" change in POI at 25 yards with a forward mounted sling.
If it helps the discussion.... I am certainly no expert rifleman or sling user, but I can control a rifle well enough with or without a sling to shoot 400/500 fairly regularly on a high power course of fire.
The lower two targets on the attached photo illustrates the issue. The left group is sans sling, the next one to the right is with a sling mounted as far back on the forearm as practical. Both groups are offhand, five rounds.
Plastic upper receiver? That's interesting, I don't know how I like that. I could see a plastic lower, but upper receiver..... Very interesting
I had similar issues with my POI moving when slung up with the 15-22 at a shoot last year. I was able to compensate and qualified as Rifleman but a barrel mounted front sight would seem to be a fix. And it took me almost a year but that is what I got around to doing. I just posted a new thread on how I did it.
http://appleseedinfo.org/smf/index.php?topic=29108.0
Cartech,
After closely watching the groupsize/poi of a shooter with an M&P15-22 I did not observe the shift which you apparently did. He had his swivel mounted to the bottom rail as you indicate you tried also. Had the weather not been intolerable he would probably qualified as his better groups were perhaps 2moa in most cases with a rifle he was shooting for the first time on Sunday. (yesterday) I did this specifically after your first post.
I am wondering (yes sometimes I wander too) if there is a problem with the barrel nut (torque) or perhaps the barrel itself on your rifle.
No one likes sending a rifle out to be looked at, but, perhaps a call to S&W at least will shed some light on your issue.
Please, by all means when you have determined the cause post the issue and the fix.
It seems from the other posts and my other experiences that this is not a platform wide issue.
In February we had 23 shooters from the Valley Forge Military Academy and College on the line with about half shooting 15/22s and there were no problems of this nature within the group.
Wish I could help more, but the suggestion is all I can offer.
George