Now to AR Bolts

[RBruce]

As if there was not enough confusion in choosing a lower from the myriad of choices, now I am on to bolts. I would have expected less confusion about choices, but no, I see milspec bolts from $85 to $300, not counting the exotic versions. I just need a Plain Jane, reliable bolt for my A1 plinker. Any problems with the $85-$100 group? Should I jump up to the $120-$130 group, or not?

Again, thanks to all who have provided thoughts and references.

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[Stevo]

Are you looking for just the bolt, or the complete bolt carrier group?

[browningautorifle]

Other than what Stevo's trying to sort out, you don't have to spend a fortune...basic is good.

[RBruce]

Complete bolt carrier group

[browningautorifle]

I'd say almost any will do. New is best. Many like the FA carriers because they have the full weight, I'm not sure it matters. Again, whatever comes at a reasonable price...

[Bill Hollinger]

Most modern manufactures are using full hammer ramp bolt carriers these days like the FAs used and are only cut slightly shorter at the auto-sear contact point than an FA carrier. Any milspec bolt carrier assembly will work fine. Yankee Hill Machine makes a nice one and reasonably priced. Steer clear of Model 1 and Delton. They are not of the best quality.

[jmoore]

I like to at least get a bolt that's been magnetic particle tested for cracks. Which usually goes along with test firing, maybe even a proof round. It's one of the few really critical parts of the system.

Bolt carriers? Mostly looking for a good gas key attach screw staking job.

The bolt that lives with whatever upper is on the M16 (Got if from Brownells some years back, IIRC):

http://www.jprifles.com/buy.php?item=JPEB-223MP

A cut and paste from JP's website:

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 C-158 (Carpenter 158) 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 C-158 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).

JP EnhancedBolt™ on left as compared to a Mil-spec variety bolt on right.

[Bill Hollinger]

You really don't need to get anything but a good milspec bolt and you certainly don't need to spend $125.00 for one. Yankee Hill Machine bolts are MP and are less than $90.00 from dealers and $70.00 off eBay ( Yankee Hill Machine YHM 5 56 Mil Spec Complete Bolt Assembly Carpenter 158 – New | eBay ). There are a few nickel boron treated bolts out there by a number of manufacturers and are reported to be really good.

The bolt carrier gas key staking is important for sure but a good heavy carrier is very nice for reliable functioning too.

[bonnie]

I use a USGI bolt and keep a spare. The extractor cut locking lug is a weak area on the bolt as said above. Kind of like the right lug on an M1 Carbine bolt. Doesn't happen often but it can.

Here is one: Bolt, Complete, AR-15/M16, USGI, HPT/MPI Marked

[vintage hunter]

What seems to be wrong with Model 1 bolts? As luck would have it that's what I'm running in both my AR's.