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Posted: 1/8/2013 7:19:30 PM EDT
Finally got my 308 Winchester DPMS Lite 20" last week, and put a couple of boxes through it.
Very nice "push" to the recoil. Nothing sharp. Still working on getting the scope tuned in. The gun is just shy of 8lbs. so it has a full size feel to it without being barrel heavy.
Sure wish it was "tighter" in the upper to lower fit. It has more side by side slop than any Oly I have owned. In short, not quite up to Oly's Standard for fit.
The first link is showing about .005" movement on the rear pin. Click on the link to get the movie.

This link shows the effect out at the barrel, about .035" Click on the link to get the movie.

The .308 next to the 300AR, 6x45, .223 and a slug from a black bear.

And both the .308 and 300AR in their mags.

While I don't like the sloppy fit of the DMPS, I'm sure it will serve me well as both a patrol weapon and hunting rifle. It's a big step up from the 300AR.


So, back to the question. Is that much play normal for this platform?
Link Posted: 1/8/2013 7:25:37 PM EDT
Mine had a touch, but I built it from parts. I threw in a AccuWedge, which got rid of most of it. Doesn't make it more accurate, per se, but it will help with the obvious slop.
Link Posted: 1/8/2013 8:21:38 PM EDT
I'll have to look that part up.
It sounds easier than shimming or some other trick.
Thanks
Link Posted: 1/13/2013 11:18:24 AM EDT
Never measured the slop on mine, but it has no trouble putting rounds through nearly the same hole at 50 yards, and keeping it at about 2" at 150 as long as I'm not messing up. If its an issue, as others have said an Accu-wedge ($4) might be a good move. If you have some RTV adhesive and time, you could make your own to shim it as well. Just be mindful not to glue your upper to your lower!
Link Posted: 1/13/2013 1:01:57 PM EDT
Of all the DPMS LR-308's and LR-308 Pattern Upper & Lowers I have seen so far, none have had a loose fit...If anything,
they were very tight overall...many times having to use a drift punch to the take-down pins to separate upper and
lower half's...
Link Posted: 1/13/2013 1:49:40 PM EDT
That's defiantly not the case here. Lots of slop and daylight through the seam between the upper and lower. Were the market not so dang tight with backorders, I'd send the rifle back. Just feels wrong to have a gun flex back and forth in the middle like that.
Link Posted: 1/13/2013 4:01:48 PM EDT
[Last Edit: 1/13/2013 4:02:25 PM EDT by dangerdan]
I think your gun is fine. I've had several .308 guns with some slop and they have been really great guns.

However, you need to ditch those rings and get standard or medium height rings
Link Posted: 1/13/2013 5:17:38 PM EDT
get you a jp tension rear pin

Link Posted: 1/13/2013 5:55:48 PM EDT
Why do you use the tension pin in the rear and not the front?
Link Posted: 1/13/2013 7:04:32 PM EDT
Originally Posted By Wheedle:
Why do you use the tension pin in the rear and not the front?



here's how JP markets it::

"Finally, the right fix for the “loose” upper/lower receiver problem. You can throw out that piece of rubber you’ve been stuffing under your rear take-down pin all these years. All it’s good for is eliminating the “rattle” in your gun. In reality, it does just the opposite of what it should. It pushes the receiver halves apart on a flexible interface. They still move when the gun discharges. The JP Precision Tensioning Pin actually pulls the whole upper assembly down and back on the lower with reproducible torque (for those really picky folks) and gives a rock hard fit to even the sloppiest receivers. Ask any bolt gun shooter, and they will tell you that a rifle loose in the stock will most likely not reach its accuracy potential. An AR with a loose upper/lower is no different. It requires no modification to the receiver. It simply replaces your rear push pin and drops right in.

A must for the “accurate” rifle!"
Link Posted: 1/13/2013 8:12:11 PM EDT


This. I had a LR308 way back when they first came out and ended up having to get one of these. The slop was ridiculous. I mean just plain bad. I tried shimming this n that, accuwedges etc. (which do nothing for side to side rocking.) this was the only thing that fixed it. Every single DPMS 308 rifle I've handled had horrible slop. Epic slop. Like "clank clank" boogie dance slop. The JP thing made it tighter than a drum.
Link Posted: 1/14/2013 7:00:34 AM EDT
Interesting. Both of my LRs were very tight. Had to use punches on the pins.
I don't understand how the JP pin works. Will investigate.
Link Posted: 1/16/2013 8:13:37 PM EDT
[Last Edit: 1/16/2013 8:14:06 PM EDT by Gos]
The angle cut pin looks interesting, but I'm hesitant to add something that takes a tool to break down a patrol rifle.

Thanks for the options everyone. And, yes those rings are already history. I have a quick disconnect set on there now with flip up irons.
Link Posted: 1/17/2013 3:26:29 AM EDT
I have 4 LRs and the slop in them is no worse than in any of my other two dozen ARs, better than some, not as good as others. My two Colt ARs, my God, you could drive a truck through the gap between their uppers and lowers but as was said, it matters not a whit when it comes to function or accuracy. The tension pin removed all slop, no question but it did nothing to improve accuracy and made taking the rifle apart a royal PITA. You have to have a screwdriver and an Allen wrench as well as having some means of holding the rifle, and putting them in is no picnic either. You have to get them positioned just right and blah, blah, blah. To me the negative far outweighed the questionable positive so I put back in the standard take down pin and have not looked back. IMO if you cannot get over the slop, use the Accu-wedge. It's cheap and does not need anything more than a pin pusher to break down the rifle. Screw that having to carry a screwdriver and an Allen wrench around should you need to break down your rifle in the field or at the range.
Link Posted: 1/17/2013 6:01:59 PM EDT
Mine was tight as hell. I needed a punch or something to push out the pins.
Link Posted: 1/17/2013 6:29:53 PM EDT
[Last Edit: 1/18/2013 2:35:30 AM EDT by Mavrick]
There is actually a cheap effective way to solve this problem. Push out the rear take down pin and open the firearm. Take a R 05 O-ring and lay in the opening between the lower and upper. Close the weapon making sure that the O-ring does not fold out into the magazine well. Push the rear take down pin back into place. The O-ring will last for some time and when it is lost or no long keeps the two halves tight just replace it. I have been doing this for the past few years and I no longer have any wobble between the two halves. I tried the rear tension pen and I never liked the way it worked when I had to break the weapon down, it was a pain in the ass.
Link Posted: 1/17/2013 6:46:47 PM EDT
Originally Posted By Mavrick:
There is actually a cheep effective way to solve this problem. Push out the rear take down pin and open the firearm. Take a R 05 O-ring and lay in the opening between the lower and upper. Close the weapon making sure that the O-ring does not fold out into the magazine well. Push the rear take down pin back into place. The O-ring will last for some time and when it is lost or no long keeps the two halves tight just replace it. I have been doing this for the past few years and I no longer have any wobble between the two halves. I tried the rear tension pen and I never liked the way it worked when I had to break the weapon down, it was a pain in the ass.


I use that trick on an early 80% lower where the pivot pin hole was too high (It came pre-drilled...) and the upper was sloppy on it. I just put it around the front upper lug and pinched the piss out of it, but it's lasted a couple years.
Link Posted: 1/17/2013 8:31:29 PM EDT
Another trick you can use is: buy some plastic dip at the hardware store (buy the black color of course). It can used in the rear lug pocket
of your lower and on the top plane of the lower depending weather you have vertical or horizonal slop between upper and lower half's.

Good Luck.

http://www.plastidip.com/home_solutions/Plasti_Dip


Link Posted: 1/19/2013 3:22:25 AM EDT
[Last Edit: 1/19/2013 3:23:31 AM EDT by DrDover]
I have a rifle that came with lose tolerances from the factory. I was not willing to accept needing an allen key for take down or any of the other hokey suggestions like the o-ring or accuwedge b.s.
I found this and it works great. Much more sano than any of the other options short of drilling and tapping a tension screw like mega machine does.
Daemon Tactical
Link Posted: 1/19/2013 5:37:08 AM EDT
Tighter the better! But not even close to being called sloppy. First deal with the AR platform is function. If it shoots accurately and reliably, don't mess with a good thing, if it has function hick-ups, then find some better pins and play with the fitment a little. Components are easy to find at both ends of the price spectrum. Best to you!
Link Posted: 1/19/2013 7:55:12 AM EDT
Originally Posted By DrDover:
I have a rifle that came with lose tolerances from the factory. I was not willing to accept needing an allen key for take down or any of the other hokey suggestions like the o-ring or accuwedge b.s.
I found this and it works great. Much more sano than any of the other options short of drilling and tapping a tension screw like mega machine does.
Daemon Tactical


Only good for the AR-15 platform though...LR-308 uses different size pins....
Link Posted: 1/21/2013 2:22:35 PM EDT
After more thought and a few more rounds down range, I'll just leave well enough alone and let the slop be. If I think of it as being "break down" friendly, rather than "sloppy" it settles better in my mind.

Thanks again for all the input.

Gos
Link Posted: 1/21/2013 9:32:50 PM EDT
I have no solution but I will say I have a Panther LR 308 and it's as tight as a frogs butt.
Link Posted: 1/22/2013 9:51:23 AM EDT
My first DPMS 308 was an oracle. The fit between the upper and lower was terrible. But all of the slop was in the front. It was side to side play. I checked it with feeler gages. I had about 6-6 thousandths of slop there.
I cut out 2 stainless steel shims. I put one on each side of the front pin. Now it's just perfect, no more slop. I don't need to take apart the upper and lower all the time. But when I do, I just carefully put back in the shims. The others were built on Billet Mega-10 sets.
If the barrel movement is because of the upper receiver movement. It's no big deal, as your scope is mounted to your upper.
If your problem is your DPMS hand guard. I'd junk it, and put an Apex on it. I love all 3 of mine. Now I'm going to drop one on an AR15. Look at them at Rainier Arms. They aren't like a Quad rail, which suck, and make you put covers or ladders on them. Also they are not smooth either. Hard to describe, but they are the best of both worlds. Put the rails anywhere you want then.
Oh yea, I'd definitely go to shorter rings. How do you get a cheek weld on that setup?
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