Taking the plunge

[BIGGLEE0351]

Well, after having some factory built .308 AR platforms (as well as M1A's and FAL's), I'm going to take the plunge and build my own .308 AR. I will use KAC/DPMS/Magpul mags. SI industries matched GEN2 upper/lower. Either Lilja 3 groove or Krieger barrel. It will be a 16 inch barrel. Geisselle trigger, Crane stock, gasbuster ch. KAC 600 meter rear buis and a KAC rifle length URX.

Now, the BIG question, what BCG/Bolt to go with. I really dont want a DPMS unit i there. I was thinking about an LMT or JP unit. Any ideas fellas??? I need some help! TIA.

 

[KevinB-KAC]

Re: Taking the plunge

I think [censored] is selling Bolt's for his .308 (which reportedly interchange with ours).
No ideas on carriers.

 

[BIGGLEE0351]

Re: Taking the plunge

Hey Kevin. thanks for the quick response!!! I have a Knights USMC issued M110 upper on a MK11 lower just sitting in the safe collecting dust. I dont want to shoot cause I dont want to ruin the "collect-ability" (if there is any). I really want the EMC but funds are scarce plus I have a few parts laying around so I could build an "interim" clone. I'll PM you cause I have just a couple of questions that I cant seem to get answered anywhere else. Thanks again for the timely response and wishing you and your loved ones a Happy thanksgiving weekend. Lee

 

[BIGGLEE0351]

Re: Taking the plunge

C'mom fellas..no suggestions for a 7.62 bolt and bolt carrier group? I was thinking about LMT and JP among others.

 

[phxfa]

Re: Taking the plunge

Im building mine with an Armalite BCG and a Noveske/Pacnor barrel in 6.5 Creedmoor

 

[BIGGLEE0351]

Re: Taking the plunge

I'm trying to stick to the DPMS/KAC mags Tom but as I dig deeper, it seems to be getting a little more difficult finding a 16" barrel for that pattern. May just have to go with a factory rifle.

 

[mdbr]

Re: Taking the plunge

My JP LRP-07 came with the bolt below.

JP EnhancedBolt™

9310 Bolt assembly with standard extractor. Available for .223 and .308 (DPMS LR-308 application).



To satisfy customer requests, we now offer the new JP EnhancedBolt™ with great life expectancy while utilizing a standard configuration extractor.

The truth is, the standard Mil-spec 8620 bolt has a number of factors limiting its performance, not the least of which is that the life expectancy of such bolts is only about 6,000 rounds. In fact, standard bolts will start to show stress cracks on the locking lugs adjacent to the extractor cut after only 3,000 rounds. Cracking at the cam pin hole and weak extractor spring tension only add to the problems of the Mil-spec bolt.



Typical bolt failure mode next to extractor cut.
The material used in these standard bolts is also not the best choice by today's standards, but if you remember the old story that explains why “Mil-spec never dies,” that applies here as well; they make them this way because they’ve always made them this way.

The latest edition JP EnhancedBolt™ is made from SAE 9310 high-grade steel. This material makes for an extremely hard surface with a tough, ductile core resistant to structural failure and a life expectancy far exceeding Mil-spec 8620-type bolts. SAE 9310 is the same type of steel used in the transmission gears of Formula One racecars, and the high-load application of a bolt assembly is ideal for this state-of-the-art material; the results of actual full-auto endurance torture tests prove it.

The design of the JP EnhancedBolt™ addresses many other fine points, the most important of which is the utilization of a standard configuration extractor. Most users want the ability to replace extractors and other parts with commonly available Mil-spec parts instead of being dependent on proprietary parts that can be difficult to acquire. Therefore, this new bolt will accept standard extractors, pins and springs.

The JP EnhancedBolt™ will now be standard equipment on all JP .223 and .308 rifles and uppers, and we highly recommend it as a complement to your JP High Performance Bolt Carriers or any rifle system. The .223 version of the bolt is compatible with any AR-15 platform using a Mil-spec bolt carrier and subcomponents. The .308 version is compatible with the JP LRP-07 and the DPMS LR-308 platforms (or clones thereof) only and cannot be used to replace bolts in the Armalite AR-10 platform (or clones thereof).

 

[phxfa]

Re: Taking the plunge

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BIGGLEE0351</div><div class="ubbcode-body"> I'm trying to stick to the DPMS/KAC mags Tom but as I dig deeper, it seems to be getting a little more difficult finding a 16" barrel for that pattern. May just have to go with a factory rifle. </div></div>
the BCG has nothing to do with mags you intend to use on your build. MEGA uses the DPMS mags and whatever you want for a barrel. I went with a Noveske barrel which mates with an Armalite bolt as per Noveske, ordered up headspace gages today for safety's sake,,,look on ARF COM for the MEGA 10 builds

 

[BIGGLEE0351]

Re: Taking the plunge

My apologies for my ignorance on the subject of "BIG" AR platforms. I'm used to Remington 700's, "regular" sized AR's, !991's and Glocks. I never really delved into the 7.62 (or larger shorts mags, which will be next

) but now that I have, I see that there is alot of info that is unique to these platforms. While I find it interesting, my biggest NEXT question is the gas system. I'm doing a rifle length gas system (Direct Impingement) on a 16 " barrel. I know that propper gas system operation goes hand in hand with reliabilty. I need stone cold reliability out of this weapon. (with a routine maintainence (sc?) schedule). Is there a "magic formula" thats proprietary to each mfg. or industry standard that is used with the 16" barrel, rifle length gas system. Any assistance would be greatly appreciated.

Real qiuck fellas, parts breakdown of what has been, will be acquired for this build:
SI gen2 matched upper and lower
Krieger M-110 barrel, shortened, reprofiled, crowned, dimpled by Marvin, Chamber by Krieger with my bolt
Knights Rifle Length URX
Either Magpul or Crane collapsible stock. Tan
Surefire suppressor mount
Geiselle trigger (not sure of which one yet). May stray on this decision and experiment with other "higher end" trigger systems. I'm also considering "drop-in" units such as AR Gold.

Thats is so far. I still have no idea on BCG's. I see I'm going to have to talk to Kevin to see what he suggests. (hear that Kev!! LOL.)

Any input from those who have been where I'm at right now would be greatly appreciated. TIA.

 

[jason8251]

Re: Taking the plunge

I have a JP CTR-02 with the enhanced bolt and LMOS. It's the softest shooting .223 I have ever fired. I would have to believe the .308 version acts the same way, respectively of course.

 

[BIGGLEE0351]

Re: Taking the plunge

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jason8251</div><div class="ubbcode-body">I have a JP CTR-02 with the enhanced bolt and LMOS. It's the softest shooting .223 I have ever fired. I would have to believe the .308 version acts the same way, respectively of course. </div></div>


Jason, I'm very interested in a JP BCG. I actually may just wind up buying a whole JP .308 rifle. (even though I want the EMC sooo bad!!!!).

 

[jason8251]

Re: Taking the plunge

Don't be scared. If you can afford the entrance fee it is well worth the ride!

 

[BIGGLEE0351]

Re: Taking the plunge

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jason8251</div><div class="ubbcode-body">Don't be scared. If you can afford the entrance fee it is well worth the ride! </div></div>

LOL, I may just have to go that route!!!!