Aero Precision M5 build...question about BCG

[bbush]

I am currently in the process of building a Aero Precision M5 in 6.5 Creedmoor. After doing a little research, I have discovered that the 6.5 Creedmoor may need a high pressure bolt. I have come up with three different brands that I am interested in....JP Enterprises, Toolcraft, and Aero Precision. The Aero and Toolcraft are roughly the same price while the JP is roughly double for the complete BCG with a high pressure bolt. My question is...how much effect does the BCG have on overall accuracy? Of the two cheaper ones, which is better Aero or Toolcraft? What do I gain with going with JP for double the price....better reliabilty, more precise accuracy, or am I just paying for a name?

 

[r.tenorio671]

...FWIW, the Aero nitrided BCG/bolt claims to be a "HP" type bolt, i.e., a smaller diameter firing pin and firing pin hole. The intent is to reduce the possibility of primer brass flow back into the firing pin hole when the round is fired, resulting in primer "cratering", a visual cue of possible over-pressured loads (not always a true indicator). Based on my rudimentary (calipers) measuring of the firing pin hole diameter of the nitrided Aero bolt, it is "smaller" than the firing pin hole found on my Aero phosphate bolt used in my M5 .308 build, but still larger than the advertised diameter of the JP bolts. As for the possible effects on "accuracy", opinions abound, but IMHO many posts appear to be anecdotal at best with little data tests across multiple platforms to support it, YMMV. A properly tuned recoil system does more to prevent the "primer cratering" typically referenced as the source/cause of "over-pressure" as well as mitigating the effects of BCG slamming back & forth during operation that DOES have an effect on experienced "accuracy". If anything, if the barrel brand you intend to purchase offers a matching BCG/bolt, get it, as this implies the barrel manufacturer has tested the recommended bolt with their product for proper headspacing and compatibility with their barrel. This assumes you don't have headspace gauges (GO/NO GO/FIELD) at your disposal to check for yourself, and the knowledge of how to conduct the checking. A basic GO/NO GO set can run about the same as a bolt, maybe even more depending on source.

The AR10/SR25 realm does not have a "true standard", unlike the AR15/M16/M4 so is can still be a crapshoot when sourcing individual parts for a build.

Reliability should be your primary objective in your parts selection, "accuracy" can be enhanced via many other aspects of the build, ammo, components (handloading), but a reliable platform is paramount first.

Edited: Forgot to include that if you get a "HP" specific bolt, you will also need to get the firing pin for that particular bolt as dimensionally it will be different from other brands/models. I'd recommend getting a couple.

 

[bbush]

I also see that the Toolcraft has a couple of BCG models specifically designed for the 6.5 Creedmoor that seem to come with a high pressure bolt with dual ejectors. I would see that as a extra margin of assurance that the spent case will be ejected properly and a plus for reliability. Is there anything wrong with Toolcraft BCGs? Are they at least the equal of Aero Precision? If I am not mistaken, they are subcontracted to make a lot of the BCGs for many of the other brands in the marketplace.

 

[r.tenorio671]

...I'm of the opinion (and it's just MY opinion) that dual ejectors is a "workaround" for an issue that occurs due to improper(?) design/assembly/specs of the host platform and installed components that adversely affects reliability. In short, a "quick fix" for a specific problem that is outside of the "norm", if such exists within the AR10/DPMS/SR25 realm. If a platform is gassed or tuned properly, one shouldn't experience "hard extraction" of a fired round that is attempting to unlock too early before chamber pressure has decreased, which has an effect on the casing rim, the BCG cycling speed, etc.. The extractor shape/design/spring(both with and without o-ring/dual spring) and material also factor in to whether a bolt is single or dual ejector. Not saying dual extractors is bad, but it again is just another deviation that increases your logistical (resupply/parts) complications....unnecessarily.

I don't know if Aero is actually producing their BCG's and bolts or contracting them, but OEM suppliers typically produce a contracted part that is spec'ed by the purchaser. Those specs will vary from purchaser to purchaser, even if the OEM supplier has a baseline design that works for the majority of manufacturers/retailers. The big consideration is "economics", does the retailer have the equipment, expertise and raw material supply source to produce the product/part themself? If not, design, spec and contract it out to an OEM supplier. Few companies in today's world produce ALL of the individual components used in their completed product(s) sold.

Both the 308 Winchester (most common chambering for AR10/DPMS/SR25) and 6.5 Creedmoor are SAAMI spec'ed at 62,000 PSI and use the same parent case. The BCG/bolt for a .308 Winchester platform is fully compatible with a 6.5 Creedmoor platform.

I would suggest that if you are using an Aero receiver set, you have a higher probability of compatibility and reliability using an Aero BCG in their receiver set. The barrel itself isn't the deciding factor on which bolt you should get, it is the "barrel extension" used on the barrel. Again, if the barrel brand offers a "matched" bolt (or complete BCG w/bolt), get the matched BCG/bolt to avoid any potential fitment issues. TBH, the Aero & Toolcraft products are fully functional and will serve the purpose. Stay within your budget as much as possible. If monetary constraints aren't a factor, then just buy a complete rifle designed and marketed for high accuracy guarantees....and if it isn't performing, exercise the warranty that comes with it.

 

[Longshot85]

...FWIW, the Aero nitrided BCG/bolt claims to be a "HP" type bolt, i.e., a smaller diameter firing pin and firing pin hole. The intent is to reduce the possibility of primer brass flow back into the firing pin hole when the round is fired, resulting in primer "cratering", a visual cue of possible over-pressured loads (not always a true indicator). Based on my rudimentary (calipers) measuring of the firing pin hole diameter of the nitrided Aero bolt, it is "smaller" than the firing pin hole found on my Aero phosphate bolt used in my M5 .308 build, but still larger than the advertised diameter of the JP bolts. As for the possible effects on "accuracy", opinions abound, but IMHO many posts appear to be anecdotal at best with little data tests across multiple platforms to support it, YMMV. A properly tuned recoil system does more to prevent the "primer cratering" typically referenced as the source/cause of "over-pressure" as well as mitigating the effects of BCG slamming back & forth during operation that DOES have an effect on experienced "accuracy". If anything, if the barrel brand you intend to purchase offers a matching BCG/bolt, get it, as this implies the barrel manufacturer has tested the recommended bolt with their product for proper headspacing and compatibility with their barrel. This assumes you don't have headspace gauges (GO/NO GO/FIELD) at your disposal to check for yourself, and the knowledge of how to conduct the checking. A basic GO/NO GO set can run about the same as a bolt, maybe even more depending on source.

The AR10/SR25 realm does not have a "true standard", unlike the AR15/M16/M4 so is can still be a crapshoot when sourcing individual parts for a build.

Reliability should be your primary objective in your parts selection, "accuracy" can be enhanced via many other aspects of the build, ammo, components (handloading), but a reliable platform is paramount first.

Edited: Forgot to include that if you get a "HP" specific bolt, you will also need to get the firing pin for that particular bolt as dimensionally it will be different from other brands/models. I'd recommend getting a couple.

I never knew the info about the nitrided Aero 7.62 bolt.

Thanks for adding valuable info.

 

[Mike_in_FL]

@bbush if you want one, they're on sale: https://www.armorally.com/shop/toolcraft-260-remington-double-ejector-bcg/

 

[_Windrider_]

I use JP BCG’s and bolts in all my large frame AR’s. Never had an issue. Expensive yes. But tolerances are tight and the quality is excellent.

 

[msgriff]

JP offers two different large frame bolts, EnhancedBolt and EnhancedBolt HP. The EnhancedBolt HP is the one with the 0.062 firing pin channel, and would be the one for SAAMI max pressure or hot loads, especially in the smaller calibers. The dimensional difference between the FP channel and the FP tip is key, no matter whos bolt you use.

 

[StaveyIL]

I ran a dual ejector toolcraft bcg for a very short time. Problem was it was extracting the cases with so much force, it was beating the shit out of the brass. Never needed 2 ejectors anyway . Switched to a RCA bolt and problem solved.
If you purchase a Hp “blemished” bcg through Rubber City Armory . Even though they are -out of stock- they typically will ship same day and I’ve never found any “blemish”.

 

[Malcolm31]

I use JP BCG’s and bolts in all my large frame AR’s. Never had an issue. Expensive yes. But tolerances are tight and the quality is excellent.

This. Impossible to beat the quality, durability, and dependability of a JP BCG.

Also…Code: 68SS0717 will save you 10% on all JP parts at JPrifles.com

 

[Wile_Coyote]

Had a Toolcraft. The BCG was OK but it did not work with 6.5 Creedmoor or 6mm Creedmoor. Switched to a JP HP bolt and it has been fine. In my other 6.5 Creedmoor I went with an HP BCG from Rubber City Armory. It has worked flawless as well. Not cheap, but well worth the money.

 

[Praetorian_6]

I'll recommend the Aero BCG if they end of taking care of me. I can vouch that 2 out of 3 of their BCGs are working and though the 3rd doesn't, I sincerely hope to report that they replaced it under warranty.

Aero Precision AR-10 BCG warranty claim

I figured I'd document this in real-time, for better or worse. I've purchased quite a bit from AP. I have purchased an M5, two M5E1s, a 16" M4E1, an 11.5" M4E1, parts kits, and several other odds and ends. Something approaching about $5k in parts and rifles. All except 1 of them, one of...

www.snipershide.com

 

[Obi-WanKannoli]

I had an Aero M5 6.5 cm that I put a Tool Craft in, had zero issues with that firearm cycling, feeding, extracting, etc. both suppressed and unsuppressed with both 20 inch and 16 inch barrels. Would buy again.

 

[Longshot85]

Who all is running an Aero M5 7.62 bolt NITRIDE on a 6.5CM.

I've built my rifle, life has been crazy busy and I haven't yet fired my rifle.

Please chime in if you're running the NITRIDE Aero bolt in a 6.5cm setup.

 

[LDO416]

I have built 3 LR308 uppers (in 308) and I have experience with the AP Nitride and Phosphate bolts, as well as the JP enhanced HP Bolt and Bolt Carrier. The AP phosphate bolt would not headspace properly on an 18 inch Criterion barrel. I purchased the AP nitride bolt, and I was able to get it to headspace properly with the Criterion Barrel. I purchased the JP bolt because my cases showed signs of cratering and primer flow. The JP bolt alleviated that problem. LR 308 rifles are notorious for showing pressure signs on cases. If I was going to build a 6.5 CM, I would definitely use the JP HP bolt. It is expensive, but it does what it was designed to do.

The dual ejectors you see on LMT/Knights bolts were originally designed to prevent stove pipe malfunctions on full auto in shorter barreled LR 308/AR10 rifles. Probably not an issue using semi auto, or longer barrels, but if you are shooting rapid fire and have this issue, you may want to try them out.