Recommend BCG and Bolt for 20" long range rifle

[va_connoisseur]

I am looking to build my first Grendel and need suggestions/help. The local precision shooting shop is trying to dissuade me from the 6.5 Grendel because he says bolts are the weakest link. That they are just shaved out 5.56 bolts and that makes the head and extractor weak and prone to breakage (and this is not a dig on them, they are good guys).

I would really like to build a 6.5 for long range 800+ yard shooting so my questions are:

a. Is the BCG/Bolt/Extractor really a weak spot?
b. If so, what is the solution?

Thanks.

[LRRPF52]

I wouldn't have high expectations from any gun shop out there, based on the gun shop realities of low pay/low skill in most cases.

You can't physically make a 6.5 Grendel bolt from a 5.56 bolt. It's impossible, because a Grendel bolt is longer. Ask them how are you going to add the length to a 5.56 bolt.

Secondly: A real Grendel extractor has plenty of material for the lip and spine, because it uses a deeper bolt face.

The engineering behind the 6.5 Grendel bolt was done early on to address the challenges of fitting a larger case head cartridge in the AR15.

I have shot untold tens of thousands of 5.56 NATO, and thousands of rounds of 6.5 Grendel.

I have broken 5.56 bolts after 10,000 rounds. I have never broken 6.5 Grendel bolts.

I'm not saying it doesn't happen, but a well-engineered bolt is going to last.

There were a lot of after-market garbage bolts from M&A Parts (Gun show grade) that attempted to make a "7.62x39" bolt and failed miserably at every aspect of design, machining, and processes, and those bolts will break left and right. They use a .125" bolt face depth, with a very thin-lipped extractor that will break of course.

There were some vendors that thought they could use those bolts and have their barrels made the way they wanted on the cheap, and those combinations are known for garbage. You see it in 7.62x39 as well.

If someone is telling you a Grendel bolt is made from a 5.56 bolt, they are just not well-informed. I used to think the same thing, until several dimensional points were made known to me, and I confirmed with my calipers. If you use a deeper bolt face and don't make the tail longer, for example, you get pierced primers due to excessive firing pin protrusion.

There were some bolts out there that used the .136" face depth, but ignored the firing pin protrusion issue entirely due to lack of basic mechanical engineering problem-solving.

The 7.62x39 market it plagued with poorly-designed bolts as well, since the mechanical engineering was done by Colt, then ignored by everyone that thought they could just hop on and go their way without thinking the problem through.


.125" bolt face depth on left, .136" on right

[NugginFutz]

ETA: ^^^ What LRRPF52 said. (He's got this down)

Your LGS's information is quite dated, and only marginally correct. Those days are long gone, though. He's just not up to date. Bolt failures are very much a rarity, these days. Most Grendel bolts are well made, properly heat treated and have failure rates on par with most other bolts, 5.56 included.

Stick with a reputable manufacturer, such as Alexander Arms, Precision Firearms, etc, and you'll do fine. I have one from Les Baer Custom and another from Tactical Ammunition. Both are .135" +/- .001". Both have several thousand rounds on them.

Mind you, too, that when I assembled my uppers, I made it a point to true the receiver face to the barrel extension so that there is no off-axis or uneven force on the bolt lugs.

Which brings up my final point. Some of the "Grendels" being sold are head spaced at .125", which enables them to use the 7.62x39 AR bolts. These bolts have a thinner, less beefy extractor than a standard Grendel bolt, and have a higher incidence of extractor breakage.

Going with a SAAMI Grendel, with the compound throat and .135" Grendel bolt, gives you the greatest chance of success and satisfaction.

[Geardo]

I've bought bolts from Alexander Arms, Texas Underground Tactical, and Anderson Arms, I found the Anderson the highest quality, and lowest price.

[Slappy]

I am a firm believer in going with what works. I have always bought my BCGs from Precision Firearms and have never had any problems. I am sure there are places that might be cheaper but this is where I started and have never went anywhere else. So I recommend Precision Firearms. BANG BANG!!

[robertc1024]

I've bought bolts from Alexander Arms, Texas Underground Tactical, and Anderson Arms, I found the Anderson the highest quality, and lowest price.

I had a day off and live near Underground Tactical. I went by there to check things out, and they said that they were the ones who made the Alexander Arms bolts. Good enough for me. Besides, they had a cool Ma Deuce on a tripod sitting in the middle of their showroom floor.

[va_connoisseur]

Thanks for the feedback.

[PrecisionFirearms]

I had a lot of issues with Underground Bolts. We have a bunch of 5.56 Bolts from them that weren't made right and after several attempts to get them to correct it we gave up. We had some issues with their 6.5 bolts and we no longer use them as our supplier.

[DRandi]

If you go the .125" bolt head space route, spend the dollars and get a LMT, (Lewis Machine and Tool) 7.62x39 bolt. It is seriously expensive but engineered correctly for that application. Bill A. was also highly impressed with their enhanced bolt series.
For a carrier, I would grab a JP Rifles carrier in QPQ finish, nothing but the best right.


LRRPF52...... that's some Purdy drawings right there!!!!




David.


edit: To answer one of your other questions, only thing different from a 6.5G and a 5.56 gun are the bolt, magazine, and barrel. Everything else is interchangeable.

[ScoutH57]

I'm fixing to order a bolt for my Faxon group buy 12 inch barrel myself.

Trying to decide between

http://www.shopalexanderarms.com/Bolts_and_Extractors-6_5_Grendel_Hard-Use_Bolt_Assembly_1.html

Or this Maxim one sold by Lilja

http://riflebarrels.com/shop/accessories/6-5-grendel-bolt/

[Slappy]

I'm fixing to order a bolt for my Faxon group buy 12 inch barrel myself.

Trying to decide between

http://www.shopalexanderarms.com/Bolts_and_Extractors-6_5_Grendel_Hard-Use_Bolt_Assembly_1.html

Or this Maxim one sold by Lilja

http://riflebarrels.com/shop/accesso...-grendel-bolt/

If I were you I would go with either one. Flip a coin??. BANG BANG!!

[85_Ranger4x4]

If you have another caliber rifle that is more readily available as a complete BCG get that and just swap out the bolts if you want a spare.

My last build was a 7.62x39 and I used an AIM BCG. I would like a spare bolt but AIM doesn't sell them separately. So my plan is to get another $99 BCG, swap out the bolt and enhanced firing pin for a Grendel bolt and a standard firing pin... and now I have good-to-have spare parts.

The Maxim bolt posted above looks interesting, I am going to have to check into that.

[4719dave]

yes im looking at the bolts as well every dollar counts but wont head aches .

[sneaky one]

Just check the boltface depth-.136- then run it. I have 3 Grrr uppers here, only 2 bolts. All are fully interchangeable. Never an issue. I push hard on them once in a while- boringville.

BTW, I'm selling 1 upper. Pm me if ?

dave, just get the best price you can. Check Ebay,,,,

[jim_bob]

If you want a fine piece of kit, go precision firearms. If you want something to get the job done, get a mil spec carrier and a bolt from Precision firearms or Alexander Arms. One look at the PF BCG made my mind up.