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POF Lower DPMS Upper


308-24-7

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Just finish assembly of my long barrel 308 rifle.. About 6 months of research and waiting for Parts. What do you think?

Parts used:

POF Factory Built Lower

DPMS Upper & Bolt from Brownells

24in Stainless G5 Barrel from Brownells 00-011-352 A04-007 M11 MUZZLE BRAKE 7.62MM SS from Brownells

A02-219 ACCU-WASHER SYSTEM 5/8-24 from Brownells

ADJUSTABLE GAS BLOCK from Brownells

Plus some other small items

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What do you think?

 

 

I was gonna give you the typical answer - you've been here for a minute, so you'd be ready for it.  Then, "1 new reply has been posted" pops up.

 

Working on pics

 

I'm glad you did that, but you still get it anyway...

 

:wwop:

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Awesome!  That a pretty speedy range report, and it makes me laugh in a way...  If I build a new semi, or buy a new rifle, I usually don't show up for work that day, or take the next day off - just to shoot that bastard!  <lmao>

 

I love it, man.  <thumbsup>

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Thanks for the approval.  No POF didnt change nor were they willing to help.

 

So after test fitting a couple of different uppers to the POF lower I found the DPMS upper matched almost perfect to the POF Lower.  Once I had found the upper to match I started looking at pin shim options for the DPMS upper.  There is not any good options for shimming there is not enough differences between the two pin sizes without doing additional machining and enlarging the DPMS pin holes.  So the best option to me seamed to be make the lower pins of the POF match the rest of the manufacturers pins size.  Mcmaster Carr offers many precision reamers of all different sizes.  The 0.278" reamer was the perfect fit for the DPMS pins.  After removing the pin keepers and springs it was a piece of cake.  Used a buddy and a hand drill. (Held straight and level)  I also had to ream out the holes of my POF upper.  This does not bother me for the fact that now I can interchange my POF upper/lower with any DPMS platform in the future if needed.  

 

I hope other with the POF system find this forum and are able to save a bunch of time and research with there own builds.  

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So went and ranot some rounds through the new upper... had some interesting things happen.. first 20 rounds were winchester factory 180gr loads.. I had 13 out of the 20 blow the primer right out on the cases? Have you ever had this happen? I also had to use the forward assist on over half the rounds to close the Breach. I run gun juice through the barrel between each of the first 10 rounds.

Next 20 rounds were steel case wolf brand 140gr. They cycled through better but needed forward assist on 4 over them. No primers blown out. No signs of over presure.

Next 20 rounds i went back to the winchester factory loads. They cycled great until number 20. Firing pin hit the primer but didn't fire. Ejected the round,, reloaded it and it fired this.

Not the dream day of shooting the new setup I was hoping for. Still able to pull OK grouping in between fumbling around.

Do you think the brownells barrel mating with the dpms new bolt will need some breakin?

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Every one of those 12 with the blown primers have some pretty hard ejector swipes on them.  Those things were hot...  :eek:

 

 

Hard to tell from the pic angle, but are the other 8 primers flattened? A couple look like they might be cratered, too. 

 

That's some hot schit.

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Did you head space that bolt and barrel? a bit concerned about useing the forward assit on so many rounds ,if you just pop open the upper can you just place a round in the barrel and lightly push it in with your finger? if those were factory winchester loads something is not right....

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So went and ranot some rounds through the new upper... had some interesting things happen.. first 20 rounds were winchester factory 180gr loads.. I had 13 out of the 20 blow the primer right out on the cases? Have you ever had this happen? I also had to use the forward assist on over half the rounds to close the Breach. I run gun juice through the barrel between each of the first 10 rounds.

When you put your "Gun Juice" down the barrel ... Did you run patches until the barrel was DRY ? If NOT... That caused the extra pressure in your chamber...

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simple explanation....they make a small precise gauge that measures the space between the bolt face and the chamber. too much or too little space and you can have big problems. imagine the round not being fully seated in the chamber and still firing off. kaboom! not a big deal with a milspec AR15, but 308s have no standard spec sheet to machine off of so using different manufacturers parts is a crap shoot. in your case, you already have parts that were not meant to work together you have modded. nothing wrong with that....and I applaud your creativity getting it running, but I wouldn't fire a single round again until I had it headspaced by a smith, or orderd the gauges and do it yourself. you are gambling with your face/eyes/fingers here man.

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