View Full Version : Which parts on a bcg generally break?
I've heard of bolts breaking at the cam pin hole and firing pins breaking. Are carriers known to go south even if they're properly staked, hp/mp tested, high quality parts? Do extractors usually take a dump before anything else?
The reason I ask is because I have spare bolt carrier groups for each ar I have and I'm wondering if that is a little overkill. Would having a couple of kits such as BCM's extractor spring upgrade kit (http://www.bravocompanyusa.com/BCM-Extractor-Spring-Uprade-Kit-p/bcm%20extractor%20spring%20%203pack.htm) or their SOPMOD bolt upgrade kit (http://www.bravocompanyusa.com/BCM-SOPMOD-Bolt-Upgrade-Rebuild-Kit-p/bcm%20bolt%20upgrade%20kit.htm) be sufficient? Can I get by with just one spare bcg for every couple of ar's? I'd hate for one of them to go down and be stuck without any replacement parts, especially in today's market. Thanks for any input.
Parabellum9x19mm
02-05-09, 01:36
the extractor is the big one. you should replace it every 5000 rounds.
you should keep spares of all those cheap parts that are subject to wear or loss. extractor springs/o-rings, extractor pins, firing pin retaining pins, cam pins, firing pins, etc....
they're inexpensive parts so best to keep them on hand. add a complete bolt to that and you're set. carriers don't really wear out unless something is wrong with your rifle (misaligned gastube chewing up the key for example)
i think people like spare bolt carrier groups because all the parts are together and ready to go... if the extractor fails in a class its much easier to just pull out the group, replace it and drive on.
I keep a complete spare BCG because it's a non-diagnostic and quick fix if in a class or similar. Pop out the complete bad one, pop in the complete good one, assess at lunch.
When they are available, this (http://www.bravocompanyusa.com/BCM-SOPMOD-Bolt-Upgrade-Rebuild-Kit-p/bcm%20bolt%20upgrade%20kit.htm)is the minimum spare parts, and I'd add a firing pin to that.
The reason I ask is because I have spare bolt carrier groups for each ar I have and I'm wondering if that is a little overkill.
In my opinion it's totally overkill. One complete BCG to back up multiple ARs is plenty.
How often do you see a bolt related failure here or elsewhere? Not all that often.
And YES. Carriers, even staked ones, can fail. I have a Colt 16 carrier where the front screw snapped. I could barely tell, but there was a gap under the front of the key. It was short stroking pretty bad.
(I took it to S.A.W. and they told me nothing was wrong with it. I pulled it apart myself and of course I was right. :rolleyes:)
It's all in how you stage your gear. I keep one spare parts kit per platform and one tool bag that covers all platforms. I take the bag and the appropriate kit(s) with me to classes.
The best backup, however, is a second carbine. I'd have to break two bolt/carriers to get to my spare as normally I'd just grab the second gun first.
The best backup, however, is a second carbine.
That's what I do. I don't own any extra BCGs at this time.
Thanks for all the advice. I noticed that the bolt upgrade/rebuild kits are now in stock at Bravo so I'll probably pick up a few of those, along with some extra firing pins and cam pins.
I do have a 2nd carbine that is nearly identical to the first. I'm still undecided if I want to sell one of my extra bcg or stick it in a build I'm currently working on.
I wouldn't go too long on firing pins. I've never read, heard, or seen a firing pin that has broken.
If there is one, it would be as rare as the Dallas Cowboys in the playoffs.
Jay Cunningham
02-07-09, 08:50
I wouldn't go too long on firing pins. I've never read, heard, or seen a firing pin that has broken.
If there is one, it would be as rare as the Dallas Cowboys in the playoffs.
What about the "special" titanium ones??
:p
What about the "special" titanium ones??
:p
Those should break... no problem. :cool:
RogerinTPA
02-07-09, 09:34
I also have a spare complete BCM BCG, Bolt and spare parts kit per AR, along with a few tools and cleaning kit. Over kill? Perhaps. I may never have to use it but I like the peace of mind it gives me. Fix the weapon asap and diagnose the problem later.
For the serious AR guy the spare parts kits really depends not only on your needs but on your level of experience changing these parts. Some guys don't care or know how to even disassemble their carbines. Those types don't really need full fire control groups or bolt carrier groups. When I'm setting up spare parts kits for friends I base it upon their abilities as well as their needs. Some guys don't need full trigger groups. If they have the knowledge and the tools to change out everything then they don't need my help.
My spare parts kits is pretty extensive. But what I take to classes or the range is'nt the same thing.
Noob question (s)
Can one buy any brand of spare parts and have them fit into any AR15??
What to buy in a parts kit??
Is a complete BCG necessary?? For each gun??
Thanks for the info.
Parabellum9x19mm
02-16-09, 02:52
Is a complete BCG necessary?? For each gun??
you need 5 complete BCM bolt carrier groups for each gun.
ha
j/k
one complete spare should be fine. spare bolts are always good...i dont think you need a carrier for each. as stated previously, the main reason for having a spare complete BCG is so that if something does fail. you can yank out the offending group and pop in a new one to save time. its a lot faster than fiddling with gas rings or extractor tension issues when you could be training.
as far as non bolt related spare parts you'll want a spare disconnector and spring, spare hammer spring, spare grip screw, spare selector spring and detent, etc...
if it is subject to wear or loss you should have spares...especially if its something small and cheap....why not have spares around?
I generally order the parts I want/need and keep a well stocked tool box. If you are a hobby shooter with some mechanical skill then just buy one complete BCG and a lower parts kit. That initially sounds expensive but by the time you buy one of the "ultimate" repair kits or some such pre packaged kit and shipping, or just decide what you need and you might not be that far off if you just got the complete kit.
I like to keep 1 complete BCG. 1 complete bolt, and at least 2 of just about any other pin/spring at all times. Some parts, like detents and springs, more is better!
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.