I’ve heard/read a ton from Colt AR15 fans regarding the other AR makers “low quality”. Some folks suggest replacing the some of the “cheap” parts but I’ve not seen much in the way of specifics.
I’m open to suggestions.
Thanks in advance.
I’m no expert but if I was buying a complete, off-the-shelf, Bushmaster I would do the following:
Some of the optional things I would look at would be:
Or another option is to run it stock for about 12 years and run about 12K thru it until something breaks… 
That’s my original plan, I’d just like to see what the good folks here think should be replaced and why.
I’m big on the why part.
Or another option is to run it stock for about 12 years and run about 12K thru it until something breaks…
hahahaha 
Buy ammo, take classes and maybe buy some spare parts, like a fitted bolt. If you use a single-point sling, either stake or locktite the buffer tube castle nut. Check your stakes on the gas key. Other than that, shoot the poop out of it. If it doesn’t work, send it back to Bushampster and make them fix it.
Lube your rifle, well, with a good lube like Slip 2000.
If I were to start over, I would either get a Colt’s or complete LMT rifle. But, if I had a Bushmaster, I wouldn’t worry if it worked well.
What you have to remember is that you are paying about $2-300 dollars more for a Colt for the extra QC; if you get a Bushmaster, you’re doing the in-field QC testing.
Shoot it and find out what happens - we’ve got Bushmasters at work with 5K-8K rounds with (after the carriers and buttstocks are properly staked) nothing more than spring and gas ring changes.
May I ask why would you replace the above parts?
So you know your gun will run reliably is the short answer.
Looking through the forum, there are several threads that address this issue from one angle or another of what brand is OK/Tier 1?; what parts do I need to change?; is Bushmaster good or bad? and on and on.
We take our stances and the dealers come out and say their lower than Tier 1 guns or parts are “as good as Colt” or “run alongside Colt” etc. and some of the time all of us are right…and some of the time some of us are dead wrong.
It looks like that we don’t ask the right questions about what we want the gun for and why we are building it or modifying like we are. The first question that we should always ask about a gun, a part or other gear is: What is it for? Is my life hanging on this part or gun’s performance? Is this a toy or a life saving tool? THAT, I submit, is where we’re going wrong. If you’re buying or putting together a rifle for shooting at the range, blasting coke cans, etc. then buy whatever cheap crap you want and that way you’ll get to learn how to clear malfunctions, tinker, repair and replace all the time.
On the other hand, if your life (or others lives) is/are going to be entrusted to the performance of the weapon, you’d better buy the best and take great care of it. Your rifle MUST work on demand every time under whatever conditions exist at that unexpected time that things go into the toilet! You are, or should be, a Tier 1 (Colt) customer of either completed rifles or genuine parts to replace the lower end crap in your economy rifle. Buying cheap to protect your life can become the ultimate expense…so don’t do it. We reviewed in another thread this week an example of the fact that it’s no less expensive to go ahead and buy the Colt instead of buying a BM or other and then replacing the substandard (for defending your life and others) parts with Colt/Tier 1 ones that are what they should be as far as KNOWN quality characteristics.
Remember, for some of you, it’s a “toy”…for others of us it’s just our life on the table. Make your choices wisely.
While mine’s only 8yrs old, it is pushing the 30-35K mark and all I’ve ever changed is a buffer spring, and the only reason I changed that is because I had an extra one laying around. The only problems I’ve ever had were mag or ammo related, nothing rifle related.
My carbine will see a lot more use on the range than it will for saving my life, at least I hope so. Then again the same goes for my Glock 29 and 20.
Should I need it for life saving situations and I have time or have an idea trouble is coming a rifle or carbine will be my 1st choice.
So I should replace all the BCG and the other parts mentioned above. But with what brand? There are tons of them out there.
I will try to search the forum for the “whys” but I find it curious that there no specific failures were attached to replacing a certain part. I’ve begun to form the opinion that most people “heard of it from someone who heard of it…” being a problem.
I’ve had my BM for a bit less than a year now, I’ve put a bit over 500 rds through it. I don’t think I need to work on it that much because of the years I spend in the Marine Corps infantry has give me a level of intimacy with the M16 platforms. I will continue to work with it as needed and will let the good folks here know if I have any trouble with it that are not mag related. Those mags are evil with any AR/M16.
I support a bunch of Bushmasters (mostly carbines) in LE venues, and have owned several in the past. My list of minimums:
-Check FSB for cant
-Restake carrier keys
-Install correct carbine extractor spring assembly (or Crane, SAW, etc)
-Replace PG allen screw with slotted screw
-Gauge pertinents
-Live fire function verification (500+/- rounds)
I’ve found that guns that get this PM and pass the live fire usually will stay quite serviceable in light-moderate LE applications.
In higher intensity uses, I’d add replacement of the bolt, gas tube, and bolt stop, perhaps some the FCG components as well.
ETA: Stake the receiver extension nut to the end plate.
Thanks for the feedback.
My FSB is good, so good I am running 4 clicks Right from mech zero on the rear sight and hold quite a respectable group at 200 yards.
The carrier key screws are staked in 2 places for each screw, pretty solid looking to me. And at 500 + rounds no issue to date.
I’ve had no extraction issues so I’ll assume the extractor is good to go, it has a little blue insert under the spring.
What is the PG allen screw?
So far so good with my Bushie. I’m going out tomorrow to help a buddy zero his. I know my zero with Q3131 and I’m going to zero with an M855 type round. My plan is to record the data for each, laminate it and keep it in the gun case. I should also do the same for some thing like American Eagle .223 Rem ammo. Just to know the 200 yard zero.
I like to zero at 200 yards with the rear drum at 8/3 minus 2 clicks. Then there’s absolutly no excuses at 100 yards. It’s all me.
4> is great.
And at 500 + rounds no issue to date.
FWIW, I like all 500 to go downrange in one session, in practical drills, getting the gun hot and dirty.
I’ve had no extraction issues so I’ll assume the extractor is good to go, it has a little blue insert under the spring.
That’s a rifle extractor spring assembly. Swap it out for a carbine assembly at a minimum. Cheap insurance. Bushmaster refuses to put the correct one in.
What is the PG allen screw?
PG= pistol grip. Bushy uses an allen head. Service guns should have a slot head. Slotted drivers are found worldwide, and easily improvised when not. Why not eliminate the need for a special tool.
Witness the frequency of the “what size is the…” questions in the various troubleshooting forums.
So far so good with my Bushie.
Glad to hear it. If you’re having good luck, you’ll likely continue to do so with a few caveats.
I like to zero at 200 yards with the rear drum at 8/3 minus 2 clicks. Then there’s absolutly no excuses at 100 yards.
I prefer a 50yd zero with the large aperture, ignoring the elevation wheel, for its simplicity. YMMV
I know a lot of guys zero at 50 or 100, but the flight path of the bullet is so close under 300 yards it really makes no difference. Hell in the off hand if I could hold sub one inch groups at 100 yards I guess I’d care. However, I’ve found that 75% of marksmanship is confidence once you have the basics down.
Thanks for the detail. Now how do I know I’m getting a carbine extractor?
Do you have a good maker or web site to order one from?
I’m thinking of getting some spare parts but all I can think of to get is a firing pin and extractor. If the entire bolt takes a crap, well BM will be hearing from me.
I understand what you mean about a slotted screw head. I’ve already replaced the A2 style PG for a CAA unit. I like it a lot.
Witness the frequency of the “what size is the…” questions in the various troubleshooting forums.
Read up on the various descriptors, options, and vendors https://www.m4carbine.net/showthread.php?t=435
I’m thinking of getting some spare parts but all I can think of to get is a firing pin and extractor. If the entire bolt takes a crap, well BM will be hearing from me.
FWIW, I stock at least one complete set of internals for each system in use, plus multiples of the most frequently replaced parts. I believe there are other posts on spare parts recommendations.
I can’t get that thread up, what forum was it under?
Fixed.
(It’s also a sticky up top.)
Many thanks.
Sorry for the delay, I haven’t had a chance to sit down and type out a reply until now.
Wayne hit the nail on the head when he said the reason is to ensure your carbine runs reliably. Now, how did I identify those parts? It’s simple; I listen to what guys like Pat Rogers say, I observe the issues I’ve seen in training classes and I test (when I have time) to see what works and what doesn’t.
Right off the bat Bushmaster is infamous for canted front sight bases and loose gas keys so take care of those issues right away. As a side note the only gas key I’ve ever had an issue with is a Colt gas key so my recommendation isn’t just for Bushmasters but for every carrier you own.
The other things like the H buffer, O-Ring or Defender and heavy extractor springs are items I run on all my carbines. They have been proven to increase reliability so I use them exclusively. I like the weight of the M16 carrier as well but that’s personal preference. Items like the stock and Magpul trigger guard are personal preference as well.
My recommendations weren’t directed at Bushmaster per say but any carbine you might rely on one day. When I pick up my Colt 6920 I’ll give it a once over as well; I’ll restake the gas key, ensure the receiver end plate/castle nut is properly staked, ensure it has an H buffer, add a Defender, clean and lube, test fire, sight in, and run a reliability check (4-5 mag dump) just to be sure she’s ready to roll out-of-the-box. The items above are just tips and tricks I’ve learned over the years and most (except the personal preference suggestions) have indeed proven themselves to be worthwhile upgrades/enhancements. They might not be necessary but think of them as added insurance.
Thanks a bunch for the detailed answer.
Mine is OK on the front sight assembly and the gas key seems to be good to go. Over 500 yds, no problems.
Now for the other parts… I’ve heard the 16" carbines cycle the BCG at a higher speed than thet standard AR/M16. True?
I gather the mods you recomend are to:
A) Put more tention on the case during extraction?
B) Slow the cycle speed of the BCG with a heavy buffer?
I take it those items you recomend are listed by the brand names so I can ID them with ease?
Thanks again!