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DPMS/CMMG feed jams...HELP!!!

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12 years 10 months ago #9845 by why2dogs
Replied by why2dogs on topic Re: DPMS/CMMG feed jams...HELP!!!
When I realized I had this problem I called DPMS, CMMG and Magpul. My concern was compatability between all three. Everyone says we are good. I thought the same thing about the CMMG being lower looking. As I slowly, manually cycle the rounds through, it looks like the bolt rides high on the back of the round. I did some youtube research and found a REALLY cool video of an AR10 cycling in super slow motion.
At about the 2:17 mark it switches to super slow and really shows the action. Granted, it's a POF side charger, but I would think the action of the bolt and charging of the round should be the same. As for your question regarding the "mutt" of DPMS/CMMG; it was a good deal from a local guy that I couldn't pass on. Love the rifle. We'll get past this. A hobby is a series of peaks and valleys, but the view from the top is worth it! Thanks for the comments and question, Dave.

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12 years 10 months ago - 12 years 10 months ago #9846 by why2dogs
Replied by why2dogs on topic Re: DPMS/CMMG feed jams...HELP!!!
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Two slightly better shots of the ramps. Hopefully the upload will work.
Note: They are not cut nearly as deep as Charlies. Barely gets the blend into the billet of the upper housing.
Last edit: 12 years 10 months ago by why2dogs.

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12 years 10 months ago #9849 by BUILDING MY SASS
Replied by BUILDING MY SASS on topic Re: DPMS/CMMG feed jams...HELP!!!

why2dogs wrote: As for your question regarding the "mutt" of DPMS/CMMG; it was a good deal from a local guy that I couldn't pass on. Love the rifle.

Well I hope it works out...I have brought this to the attention of some one in greater knowledge than myself....we will see what he has to say...(MSH)...
Anyway...not to be my old self...but remember in referencing this..that ArmaLite is the "True" AR-10...and all others are made after the fashion..so if you would...please refer to the upper and lower accordingly...
I know...what an A hole..besides being a Proud member of the Pride....for your benefit..to get the correct info...it is better to use the "Proper Nomenclature"
being the right terms..... I will help in anyway I can.... B)
I take my rifle seriously....not to be undisputed.... :pinch:
BMS....

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12 years 10 months ago #9855 by why2dogs
Replied by why2dogs on topic Re: DPMS/CMMG feed jams...HELP!!!
The term "mutt" was to reference that fact that the rifle was not a pure bread of one manufacturer. Not to demean the class of rifle. As so eloquently put by Mr. Marlon Brando..." I meant no disrespect". Again, thank you for your help.

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12 years 9 months ago #10385 by why2dogs
Replied by why2dogs on topic Re: DPMS/CMMG feed jams...HELP!!!
Well...I received my upper back from DPMS yesterday. The repair from in the box stated that the "Diagnosed Malfunction" was "extractor letting go of empty case". (The one round I was able to fire did get stuck in the chamber) The "Repairs Performed" section stated "replaced extractor and spring. Reground feed ramps". In looking at the ramps, they are cut much deeper to where they are now blended into the upper casting. I mounted it on my lower and loaded some plastic dummy rounds to see how she cycled. Smooth as silk. Much easier pull on the charging handle and bolt seated all the way into the breach. Very happy. Next, I tried some live ammo. Cycled 4 rounds several times. No issues; however when inspecting the rounds, I noticed the tips of the bullets were striking the top of the feed ramps. I will upload some pictures from home. Also, the primers had a minute indentation from the firing pin. I sent pics in an email explaining this to DPMS and this was their reply. Please read and let me know what you guys think? Thanks, Dave.
"With the AR style rifle what you are seeing is normal. The soft lead tip hunting rounds will get beat up when feeding into the rifle. I use Hornardy 165 soft point and after loading 1 round 4-6 times it looks pretty beat up. It will not affect the accessory of the round at all. I used to take the rounds after cycling them that many times and put them in a separate mag and use those for fun days at the range. Then I tried them side by side to new rounds and saw no difference in the accessory at all out to 300 yards. The mark you are seeing on the primer is because AR rifles have a free floating firing pin. If that was not on the primer I would be worried. There is nothing to worry about the round will not go off."

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12 years 9 months ago #10386 by Charlie
Replied by Charlie on topic Re: DPMS/CMMG feed jams...HELP!!!
Cool!

Next time I'm at the range (this weekend) I'll do the chambered round test.

Charlie

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12 years 9 months ago #10394 by why2dogs
Replied by why2dogs on topic Re: DPMS/CMMG feed jams...HELP!!!
Thanks Charlie. Let me knkow what you find. I hope to make the range Sunday.

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12 years 9 months ago #10444 by why2dogs
Replied by why2dogs on topic Re: DPMS/CMMG feed jams...HELP!!!
Update. Hit the range Friday afternoon. Ran the rest of my Winchester and Hornady down the pipe. Every round cycled nicely. What a relief. Grouping was a little inconsistent, though. Tight 3 rounds then a floater 3" down to the left. Technique? Cheaper Centerpoint scope that came with the rifle? Had one Hornady ftf. Primer was pinned, so the rifle appeared to do its job. Besides the odd groups, I had one other issue. Every ejected casing was dented on the side. I was by myself, so nobody there to try and watch what was happening. Looks like the shell is striking the deflector and causing the damage. Sent an email to DPMS asking for their input. Replied with a nice tip. Suggested a small piece of velcro in the deflector face to cushion the impact. Also keeps the rifle from getting marked. I have a Nikon Monarch coming back Wednesday and mounting with a GG&G mount. Will see if it that helps the groups. I'll also let you know how the velcro works. Thanks, Dave.
The following user(s) said Thank You: JeffSavannah

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