survivalshop

Only cycling problems I have with this rifle is when I use PMags , no kidding . The rifle does have a soft recoil ,like push ,not a shove . Target photo's , I shot the 20" first , then went to 16" , then back to the 20 " & so forth . I had to shoot the 20" first just to see where it would hit , because I had the scope set for 200 & I put it back to the "0" setting & wasn't sure just turning the knob back to the "0" setting , if it would be on , guess it works . I like the looks of the early CMMG 308 lower & SI Defense upper , but I have not liked the fit between the two or may be its one or the other . Any way , I'm starting over on this 16 " barrel , just because I can , if for anything else . I'm also going to take a trigger pull reading on both rifles .

Wow !

Load it then shoot it & clean the brass . I would remove the de-primer pin from the sizing die stem & resize the primed brass before reloading . Should not be a problem de- priming the mil crimp , I do it all the time .

Kinda makes you wonder ? Opening up the gas port is not always the first thing I would do , with out checking other things first , like sending it back to Armilite , but what ever works . <dontknow> I only had to do a gas port change on one rifle & that was a 10 1/2 " barreled replica XM 177 select fire rifle I built & it made the rifle sing on full auto with out missing a beat .

I took both the 20" & 16 " to the range today & the fog was just lifting & about 72 deg. & no wind . Shooting same batch of Hornady 168 gr. match bullets out of both rifles & I have to say the 16" didn't stand a chance at all . The 20" just flat out puts one hole groups & the 16 " always had flyers that just screwed up the groups in the 16". I even tried my new loads of 168 gr. SMK with 42,5 gr. of IMR 4064 , with out much difference . I have not tested or Chrono'ed this load yet in ether rifle . My glasses fogged up with every shot , but they did it with all the rifles , so can't blame that. I will post the target photo's as soon as I down load them . Shot @ 100yards. There could be several factors that make such a difference in groups , the 20" has a PRI brake on it ,the 16" has a VLtor brake /flash suppressor , & there is a deference ( slightly ) in Geissele triggers , but not much , they both are nice . I have another brand new DPMS complete lower & new TM. upper & what I think I will do is just rebuild the 16" on the TM upper & use the DPMS lower with the Geissele trigger & see what happens & also order a PRI brake for it , just to make it a little more even. I like that brake any way . So let the rebuilding begin , one aspect with changing it to a DPMS lower is I will probably be able to use PMags . I also took my 308 Mossberg bolt gun to try it out , only has about eight rounds through it be fore this , so not at all broken in .

That should be the right one. Could be just a bad part (receiver extension ) How long is the Slash spring & how long is the other DPMS spring ?

You can experiment with in limits . If you start showing signs of over pressure , back off , add a little at a time & see how they do . All barrels & chambers are different , so one shooting differently than another is normal .

I have two receiver extensions in front of me , one was supposed to be a Milspec , it has the correct out side diameter of 1.15" but has the slant at the back like a Commercial extension & its showing 6 15/16" where the buffer retaining pin sits. The other Commercial one is exactly 7" inside depth & it has the Commercial out side diameter of 1.17" . You may well have a bad or out of spec extension . The Milspec one I have, worked with out any problems, yours seems a little short & that will definitely cause problems. My DPMS 308 Carbine spring is 11 1/4 " long & has 29 coils in it .

Is the receiver extension a Commercial or Milspec ? Have you tried a DPMS 308 carbine spring ?

I use it & haven't noticed any problems . Was a bit leery at first , but I have two or three loadings with it , with some having a line in it . I don't use Max. loadings so, not sure how that would effect it . I thought it would come out with firing , but the marks or discoloration was still there on some .

Strap wrench or Crescent wrench & tighten /loosen three times . Doesn't look like you have to worry about lining up the opening for the gas tube, unless the a flat has to align up .

Tactic's & Training category ?

That's real good of them . Can't wait to hear testing results .

<munch>

I don't think you pulled a chain , maybe enlightened some , including me . These threads some times have a mind of there own , around here <dontknow> . I can see the new calibers flat out shooting the 308 ( yes , that was a pun ) I will be using a host of different bullets all in the 168 gr. weight to see what the 16" can do against the 20" with same hand loaded ammo . Barnes bullets come to mind , there ME/LE for one & I have a few other no name brands ( I don't even know who made them ) that are not known today, to try. The only thing I have read of the 168 gr. bullets a long range was in respect to the lethality at lower velocities . Maybe I'll find some thing no one else has Or what every one already knows , what the hell , I'm retired , I have some extra time now . <laughs>

Man 98, you get a new chop saw for making 300BLK brass & you chop $hit up at the drop of a hat. <thumbsup> I weigh all my brass after cleaning , sizing & de-priming & trimming , my last batch of once fired LC had 23 @ 175 gr. weight class & 49 @ 180 gr. class. They are all close to those weights ( example 174.8 - 175.8 gr. ) I load them in separate classes that way , I have found that , on a Chronograph, if you load them the same charge, the heavier brass will always have a higher Average Velocity. Makes you wouder if some flyers are not caused by this factor .

If I had to use the new DPMS low profile , I would need a riser & ultra high rings . I have to use ultra high rings as it is to get a good sight picture with my cheek weld . Watch what ? Just because we use the DPMS Pattern, doesn't mean we have to follow them like a lost dog. Plenty of manufacturers out there making them like the original height rail. We don't need no stinking DPMS ( or Armilite for that matter ) <lmao>

There is nothing about range in the posters question ( he hasn't posted since ? ) So if your looking to make an 308AR more accurate , that question has been answered , why beat it to death . Seems like there's no question about the validity of N Jensens credentials for trigger time or match experiences , but do you know any one who tried matches with a shorter barrel ? With what type of rifles were these matches shot ? Its going to take me a bit to get to the long range, range , but I will compare a 20'HB to a 16" HB this summer & the only thing that I believe will be the difference is Velocity of the projectile @ range & that doesn't mean poor grouping . I've seen that graph before.

A Superior springs (Tubb"s ) should work in any receiver extension you want to put it in , as long as you use an AR 15 for an AR 15 & an 308 AR /AR10 for a 308 , spring.

TM response

I think I paid between $30-40 for my S/S pins & they work great . That mix is interesting & since you brought out a photo , you have to buy some & give us a review <dontknow>

It won't do here ! An AR or it doesn't count <thumbsup>

Could be a problem with the bore for the spring & buffer , burr from machining or just filings in there . Seems a few people are having problems with that pin on the TM. Lowers . I will Email them & ask what is up or you can go to there web sight , they have a Forum there, last time I looked.

http://www.tacticaloperations.com/SWATbarrel/ This is from a thread that I think ,Drew started.

I'm surprised it came from 98 & not you. <laughs>