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Posted: 3/26/2010 8:15:57 AM EDT
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Who cares where your kit/rifle came from...this thread is not about that...lets continue!
I was talking with some buddies yesterday and the topic came up. Two of us have AR's in this caliber that don't have any problem getting ours to go BANG every time. The most recent built I did for my nephew does. All three kits came from the same place, the two that fire every time were pre-Obama election the one that is not running properly is post election. Makes me think something changed in a spec somewhere during the crazy rush!?!?!?!? Was wondering; You guys who are having issues when did you build/buy yours? Before or after? This does not include a gun that has already been modified. Any one tried those uppers on other lowers? I am wondering if the problem is being caused by a change in the hammer or hammer spring. I think I'm going to test my theory and put my nephew's upper on my lower. I guess it could also be a spec in the bolt or firing pin that has been changed. I might even swap BCG to see if my nephew's gun still doesn't go bang when it supposed to. I am thinking there has to be some reason some run fine and other do not. According to my tracking number my Model 1 7.62X39 firing pin will be delevered today, so I can the nephew up and running. So I guess what I'm really asking is what have you tried to make your 7.62X39 gun run? |
My brother had the same problem,FTF with his latest build in 7.62x39. It would fire on the first shot, then have a FT Feed, or FT Fire on the next round. After a long go-around with trimming firing pins (always fired on first round), swapping magizines, changing ammo etc., he sent the rifle back to MGI. Their response was, "The bolt Carrier is out of spec.and is dragging". They said they were waiting on new BCG's and would replace his. That was a month ago... He is still waiting for his rifle.
Jack 
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I am using Model 1's fairly new firing pins enhanced for 7.62x39 in both of my said caliber ARs and have had zero failures to fire with any ammo since switching. I do have Geissele triggers in them that have pretty stout hammer springs.
And the failures to feed are nonexistent with the C Products 10 rounders and 20 round USA frankenmags in my guns. |
He is using C Products Magazines, but the same ones work in my 7.62x39. I don't believe the BCG was traveling back far enough to pick the round up properly. I'm using all DPMS with a Colt barrel and no problems after I trimmed my firing pin stop a little. I just hope I don't start puncturing primers when I switch to boxer primed brass.
Jack
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Quoted:
. I do have Geissele triggers in them that have pretty stout hammer springs. And the failures to feed are nonexistent with the C Products 10 rounders and 20 round USA frankenmags in my guns. Very interesting. This is the kind of input I was looking for with this thread. If they use a heavier spring or hammer then the issue must be in the bolt or firing pin. Now that I have one of the Model 1 enhanced firing pins I need to put the mic on the firing pin from my AR that works fine without mod. I'll keep post that info when I get a chance. Thanks for the mag info too...I keep forgetting (working on a 80% receivered AK-47 project) to order some of their 10 round mags for my new build (got the barrel yesterday) and for my nephew. |
| I just finished a build using an ARP 7.62 x 39 barrel and Super bolt with standard AR-15 firing pin. Wolf steel case lacquered ammo fed out of new CP 7.62 x 39 mags and it has never missed a beat. The ARP Super Bolt is set up from the get go to use standard firing pins and give .038 inch firing pin protrusion. FCG is a RR NM two stage tuned by WOA and set to 3.5 pounds. |
| I did put the MGI bolt and firing pin in my gun from the get go. It has a Model 1 Upper and bolt carrier. I also use the RRA National Match trigger. No heavy hammer springs for me. I like nice triggers. This setup works flawless with the old East German lacquer coated and Chinese copper washed ammo I have. I haven't tried the “animal” brands. Of course my reloads are no problem. I've even thought about swapping back to the Model 1 bolt when I shoot my reloads as I have “heard” the MGI bolt doesn't stand up to too much abuse. Just save that one for the commie stuff. |
Ok,  so you're shooting Boxer primed re-loads with the 7.62x39 modified bolt and extended firing pin. Thanks for the information.
Extending the firing pin for the deeper recesed Berdan primers and then returning to the "Flush" Boxer primers was one of my concerns as I didn't want to start perferating primers. Jack
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Quoted:
I just finished a build using an ARP 7.62 x 39 barrel and Super bolt with standard AR-15 firing pin. Wolf steel case lacquered ammo fed out of new CP 7.62 x 39 mags and it has never missed a beat. The ARP Super Bolt is set up from the get go to use standard firing pins and give .038 inch firing pin protrusion. FCG is a RR NM two stage tuned by WOA and set to 3.5 pounds. "Super bolt" that is my next purchase for my current AR build....I liked the idea of being able to use a normal AR FP and ejector. Got my Model 1 20" barrel in and the enhanced firing pin Friday, but didn't have a chance to do much more than open the box to fondle the new parts! 
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I just finished a build using an ARP 7.62 x 39 barrel and Super bolt with standard AR-15 firing pin. Wolf steel case lacquered ammo fed out of new CP 7.62 x 39 mags and it has never missed a beat. The ARP Super Bolt is set up from the get go to use standard firing pins and give .038 inch firing pin protrusion. FCG is a RR NM two stage tuned by WOA and set to 3.5 pounds. "Super bolt" that is my next purchase for my current AR build....I liked the idea of being able to use a normal AR FP and ejector. Got my Model 1 20" barrel in and the enhanced firing pin Friday, but didn't have a chance to do much more than open the box to fondle the new parts!
Is there any concern about using a standard extractor with this round? |
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not all 7.62x39 bolts can use the standard extractor.
But if your planning to buy a new bolt I have heard alot of good things about the ARP design (uses stock ar15 parts, gets you proper protrusion without modifying your firing pin etc) my ARP upper is arriving in two days so I will have personal experience with it to report on the success that everyone has with them. |
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My AR Performance barrel and bolt arrived this evening. If work calms down a little I might have it put together by this weekend for a range trip. ETA - Assuming my PRI .308 muzzle brake arrives in time for that as well. I was going to buy their package deal, but they don't have the 20" barrel. I scraped the Bushmaster 20" banned barrel, so I'm was kind of stuck building another 20" gun. I can't wait to hear some "in the field test info" on their bolt... |
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not all 7.62x39 bolts can use the standard extractor. But if your planning to buy a new bolt I have heard alot of good things about the ARP design (uses stock ar15 parts, gets you proper protrusion without modifying your firing pin etc) my ARP upper is arriving in two days so I will have personal experience with it to report on the success that everyone has with them. I just got my refund on the MGI bolt I was cursed with. Im now waiting for my ITS superbolt which uses standard extractors and after my fiasco with MGI and breaking extractors im a little gun shy (pun intended) EDIT Didnt realize the ARP bolt everyone refers to is the ITS bolt from ARP... :P |
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I'll have to call them and get the part number for the 7.62x39 and send the order with a M.O., as I don't trust order via a CC. Once bitten, twice shy as the saying goes and once was definitely enough for the CC issue for me. Thanks for the info on the firing pin! |
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I'll have to call them and get the part number for the 7.62x39 and send the order with a M.O., as I don't trust order via a CC. Once bitten, twice shy as the saying goes and once was definitely enough for the CC issue for me. Thanks for the info on the firing pin! But you trust a MO? |
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A US Postal money order can be tracked and a reissue obtained(in certain instances) should something unforeseen occur. Additionally, the MO can be sent with tracking and explicit instruction(s) or request(s) should such be necessary(of course, no guarantee the M1S would pay any attention to such instruction or request). After having experienced the CC issue myself, I'm somewhat hesitant to place another CC order with M1S. |
| I have the Model 1 upper and a Rock River lower with the RR NM two stage trigger that Bill Springfield tuned up for me. Has a 3-31/2 # very clean break. Also have the enhanced firing pin. No modification to the bolt. Works 100%. Once you get it running be sure to run several hundred rounds through it and keep the bolt well lubed on the inside. If you do that and use the CProducts mags., you should have a 100% reliable rifle. I now have about 1500 rds of mostly steel cases through mine and love it. Good luck. Phil |
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