Bolt carrier questions?

[holy cow]

I have had many bolt rifles built through the years and understand the building process and technical points to having them built. I have always wanted to have an AR built and have finally took the plunge into it. Lately i have done so much surfing on parts and info when i find it to read. As much fun it is to have stuff built it is as much fun for me to understand all its functions and why things work the way they do. It does seem to me so far that they are straight forward and with some tools of your owne and common knowledge they can be put together by yourself with drop in parts. This leads me to bolt carrier groups. I see many offered in many styles. I opted to go with a Fail Zero on an upper that Steve ( RangerWalker71 ) is building for me. Another was a coated 1 offered here from a vendor for another upper i am doing. I see national match, heavier and lighter bolt carriers at big price ranges. What makes 1 better than another and do you use lighter or heavier bolt carriers for different applications that are used only for certain builds? I will be using my stuff to varmint hunt, shoot different ranges at the club and get into some different matches that the rifles will be allowed in. I am not going to be doing mag dumps with these rifles and they will not be fully automatic nor have a can on them. So what is it with these different bolt carriers and their cost? I am not bitching about cost of parts as you get what you pay for and have no problem paying for good equiptment and parts when building anything. I have many other questions reguarding these type firearms and hope to be able to just shoot the shit with someone sometime that knows and understands these inside and out.

Dan

 

[ShtrRdy]

Re: Bolt carrier questions?

I'm not sure about this but I think the lighter Bolt Carrier is for those wanting a faster cycle time, for 3-gun and other applications.

I had a target/varmint AR built for me about 15 years ago. The gunsmith ended up using a plain Bolt Carrier because it seemed to provide better accuracy. He had a real purdy chrome Match Bolt Carrier he was going to use but he said it didn't seem to work as well. I don't know if any of that makes sense but it sure is a tack driver. After he built the rifle I had him build a carbine upper and he used the "Match" Bolt Carrier in it.

 

[BobD]

Re: Bolt carrier questions?

Dan,

You will see (other than just tolerances) varying finishes, alloys, hardness and coatings among different offerings. They end up being a combination of claimed improved performance with less friction and better finishing as well as surfaces/crevices that are easier to clean and are less prone to attract fouling. Higher end offerings will likely come with quality assurance controls like Magnetic Partical Inspection (MPI) and High Pressure Resistance testing (HPR). It costs significant amount more for those types of testing and the prices usually reflect the extra 'confidence' that your bolt and carrier will perform as intended.


Some cheaper options may have small burrs from manufacturing and cause additional or unwanted contact and friction. There are some companies that also provide the service of polishing your current BCG.

I don't have enough first hand experience with a large variety of companies to attest how different the the higher end manufacturers are from each other. I wold propose to look for one from a company that is well regarded in machining. With that said, I'm unaware of a third party manufacturer that makes cream of the crop carriers above getting one that comes from the same company that designed the upper.

They are all of course interchangeable, but in my mind a part that was designed and likely tested on their own products would fit and suit nicely in the upper receiver they built as well. That is unless you are looking for a special finish that is only offered elsewhere.

It's difficult to tell what you need in regards to weight when dealing ith an AR type platform. There are several variables to account for that can alter the speed of everything moving...

-buffer tube weight and srings,
-length gas system and nominal amount of air forced in
-weight of bolt carrier and bolt components
-surface of bolt carrier
-etc...

Without knowing these ahead of time it's difficult to determine what your needs may be. I would suggest finding or borrowing a standard style bolt and carrier to see how your rifle operates after the rest is complete. If not possible, I would look into some of the tried and true tested pieces from one of the bigger players in the business. The fact you are building yourself leaves a lot unknown. When buying complete rifles you can often know from reputation whether a certain model is commonly over/under or properly gassed.

I believe if you fork over high dollar before knowing this you may have to chase or compensate with the other parts to bring it back (if you can identify that's the root of the cause opposed to a misaligned gas block or something of that nature), costing even more in the long run.

Best of luck on your build,
Look forward to seeing how it tuns out-

 

[kingjr]

Re: Bolt carrier questions?

for ease of cleaning and lubricity it is hard to beat the chrome and NIB coated BCG's. I run them in all my rifles

 

[Rprecision]

Re: Bolt carrier questions?

Really for your use a standard M16 bolt (added weight over a AR) which is MPI tested is good to go. The #1 failure of BCG's is a improperly staked gas key.

Some may be a little easier to clean, look pretty, Etc.

 

[Ammo dog 2311]

Re: Bolt carrier questions?

Does anyone know where you can even find a bolt carrier group for a 308 platform ? Young, JP groups are - out of stock-

 

[holy cow]

Re: Bolt carrier questions?

Can someone here chime in and let me know why and what application you would use a lite bolt carrier group verses a national match type or a heavier bolt carrier? If you were having an AR built to hunt with and shoot some paper or steel or maybe some slow fire type matches would their be a reason to use 1 than the other? And if so does that change what buffer and buffer spring you would use. Maybe i am making something in my mind complicated when it really is not.

 

[rjbyrd]

Re: Bolt carrier questions?

Fulton armory has 308 bolt carrier groups. I just used one to finish my dpms build.

 

[azimutha]

Re: Bolt carrier questions?

You might check with CPWSA. I just ordered a JP low-mass today.

 

[Ammo dog 2311]

Re: Bolt carrier questions?

Thanks, goin to get one asap

 

[aloreman]

Re: Bolt carrier questions?

You would use a heavier bolt carrier and spring if you wanted to slow down the unlocking of the action. Works great for shooting Heavy bullets like 80s. Less recoil and less brass damage