swapping bolt carrier groups/spare parts

[TALLEY1013]

I have a quick question for you guys with a lot more knowledge than me. I am taking a 2 day carbine course next month and want to get some spare parts for my RRA entry tactical such as firing pin, retaining pin, cam pin and extractor. I was looking at BCM for the parts and really liked their mpi auto bcg. I am kicking around the idea of just buying a new bcg instead of just the parts I want. Is it advisable to install a complete BCM bcg and use my RRA as a back up for spare parts? My carbine has approx. 1500 rounds through it so far. I have heard both for and against swapping bcg's and wanted to see what you guys think. I really like the idea of having a quality BCM bcg but only if it is safe to use in my used RRA! Also, what spare parts other than the ones listed above should i consider having with me when I take the course. I know that RRA has a less than stellar record so I want to make sure I have all the bases covered if my carbine takes a dump. Thanks for the help.

ET

[bkb0000]

not only will you not have any problems putting the BCM in there, i recommend it.

[TALLEY1013]

thanks. that's kind of what i was thinking but i have read elsewhere that changing bolt carrier groups could potentially cause headspace issues. thanks for the input. from what i have read here i dont think i can go wrong with BCM.

[Complication]

If you're taking it to a carbine class and/or are going to put it through hard use, this might help: https://www.m4carbine.net/showthread.php?t=7376

Even if you don't have the time or money to do all 5 of those things, being aware of potential pitfalls or problems may help you diagnose any problems you come across--or at least be aware of some of the potential limitations or "blind spots" of your gun.

[Blankwaffe]

No doubt the BCM BCG would be a very wise upgrade and is top shelf.
But I think the best deal going to date is the DD BCG from G&R Tactical:
http://www.gandrtactical.com/cgi-bin/commerce.cgi?preadd=action&key=M16-BCG&reference=/cgi-bin/commerce.cgi%3Fsearch%3Daction%26keywords%3Dgroup%20bolt%20carrier%26searchstart%3D9%26template%3DPDGCommTemplates/FullNav/SearchResult.html
Plus the DD BCG has a large spool M16 firing pin rather than the small spool AR15 type.Nit pickin I know,but still.

Otherwise I'd do as the others recommended and follow the upgrade suggestions from gotm4 and Rob_s,particulalry the RE endplate/castle nut staking etc..

I'd also look at installing a known quality action spring and H buffer such as:
http://www.gandrtactical.com/cgi-bin/commerce.cgi?preadd=action&key=HBCAR&reference=/cgi-bin/commerce.cgi%3Fsearch%3Daction%26keywords%3Dbuffer%26searchstart%3D9%26template%3DPDGCommTemplates/FullNav/SearchResult.html

After the upgrades take the rifle out and run it to make sure all is good to go before you leave for the class.

As far as spares,Im dont attend many classes,but when I do go I generally like to have an extra rifle on hand in case my rifle goes down and I can't get it running right away.That way I can fall back to the spare rifle and fix the other when I have time and I don't miss out on anything during the session.
But at the very least I always keep a BCG,charging handle,LPK,action spring,buttstock and assorted tools in my range bag 24/7/365.Don't forget to take some CLP/lube and a cleaning kit.

[uscbigdawg]

For the classes I've done and in all 3-Gun competitions, I carry a complete extra BCG in my kit of goodies. When in doubt, swap 'em out. No issues (obviously having checked headspace and function firing everything first).

Rich

[Quentin]

I certainly have to agree with Blankwaffe. I was looking for a BCG and due to his recommendation earlier chose Daniel Defense from G&R Tactical.

It's a high quality component and of course gets all six M4 Chart checkmarks for the bolt/carrier group. It dropped right in my ArmaLite middy and has functioned 100%.

On top of that G&R shipped quickly and the price was right. This is pretty much a no-brainer upgrade, any AR with a questionable BCG will improve greatly with a BCG upgrade from DD, BCM or a very few others.

[TALLEY1013]

Blankwaffe
will a regular size firing pin work in the DD BCG with the large spool firing pin? I am a new guy and didn't know there are different types of firing pins. It looks like I am going with the DD as long as it is compatible with the standard firing pin that I will have in my backup kit. Thanks again for the help guys.

ET

[Blankwaffe]

Blankwaffe
will a regular size firing pin work in the DD BCG with the large spool firing pin? I am a new guy and didn't know there are different types of firing pins. It looks like I am going with the DD as long as it is compatible with the standard firing pin that I will have in my backup kit. Thanks again for the help guys.

ET

Yes the AR15 small spool (and M16 large spool)firing pins will work in the DD BCG,and any other shrouded bolt carrier such as the AR15 enhanced carriers we see nowadays.
The AR15 small spool firing pin was modified to work with the unshrouded carriers and notched hammers.
I personally think the large spool firing pins are better to use in the shrouded carriers as they have a larger contact surface to engage both legs of the firing pin retaining pin more evenly,and its the original design.Some may say thats nit picking,but is my preference.

[TALLEY1013]

got it. thanks again for the help.

ET

[BufordTJustice]

not only will you not have any problems putting the BCM in there, i recommend it.

+1

It would be a definite improvement. Headspace should not be an issue. Upgrade to BCM with confidence.