A day in the life of a BM LE Dealer

[C4IGrant]

As many know, I recently received my BM LE account. Well today I got my first shipment of their super light carbines. (http://www.bushmaster.com/catalog_xm15_BCWA3F16SL.asp)

Since this is my first order, I thought I would take the time to document what I found.

On initial inspection, the weapon looked very good and clean. No dings, scratches or blems. I did notice two things though, the castle nut was NOT staked and the FSB was not F marked. Upon field stripping the gun, I found that the gas key was barely staked (meaning that that the stakes were not actually touching the screws) and that the screws used in the gas key were on the small size (head diameter was undersized). This issue can result in a gas leakage problem. I then removed the extractor from the bolt and found a blue extractor insert.
The gun came with M4 feed ramps, carbine buffer and a commercial receiver extension.

Un-staked Castle Nut


Poorly staked Gas Key


Blue extractor insert, no Crane O-ring


M4 Barrel extension and M4 upper receiver



The small gas key screws really needed to be addressed so I went about removing them. I was interested in seeing how much inch pounds of torque it would take to remove these screws. The first screw came out at about 36-40in lbs.

Torque setting for removal of gas key screws



Once the screws were removed I looked at them and the gas key for any signs of adhesive. None was used. Using light torque, no adhesive and light staking is a recipe for disaster IMHO.

As I said earlier, the gas key screws looked on the small side to me. I was right. My calipers tell me that they were on the small side and no amount of staking was ever going to get the sides of the gas key to touch the screws. So I changed them out for heat treated, aircraft certified torx screws.

Size of the BM factory gas key screws


Size of Torx bolts we replaced the factory gas key screws with



I followed the following steps for the installation of the gas key:

1. Degrease the gas key, bolts and bolt carrier.
2. Verify that the gas key base is square.
3. Apply a THIN coating of rocksett onto the torx screws.
4. Torque down the screws to 60in lbs.
5. Stake the gas key properly.

Degreased bolt carrier, gas key and Torx screws



Rocksett getting applied


Torque setting for re-installation of gas key screws


Gas key getting staked


Finished product



After the gas key was re-installed, I moved onto the bolt extractor. I changed out blue extractor insert for a black one and added a Crane O-Ring. I then upgraded the carbine buffer to an H buffer. Moving onto the castle nut, I double checked the torque setting on it and then staked it.

Upgraded extractor


Staked castle nut


Factory Carbine buffer and installed H buffer




The last issue that seems to plague many shooters is the low front sight base. This one was NOT rated for a flattop (F marked) and so I went ahead and installed a taller front sight post.

Comparison of the two front sight posts (factory post on right)


Taller front sight post installed



Now we are all done and everything is good to go and back together. That wasn't so hard now was it?


C4

[C4IGrant]

All done and ready to go!





C4

[markm]

Very thorough indeed!

Are you sure the FSBs needed the sight post changed? I mean... is it possible they just didn't have an "F" stamped into them?

[C4IGrant]

Very thorough indeed!

Are you sure the FSBs needed the sight post changed? I mean... is it possible they just didn't have an "F" stamped into them?

I measured it and it was shorter than an F marked FSB. The taller front sight post just gurantees that the end shooter will be able to use whatever BUIS they want.


C4

[Robb Jensen]

Very cool.

[JB2000]

Excellent work! You should offer that as an upgrade package to all of the Bushmaster and other "tier 2" owners out there. My Stag came with the blue insert, standard buffer, and un-staked castle nut. I've fixed the first two but need to torque and stake the castle nut still.

[HES]

I measured it and it was shorter than an F marked FSB. The taller front sight post just gurantees that the end shooter will be able to use whatever BUIS they want.


C4

Question...where on the front sight post is the F mark found? Also, is the correct procedure for changing and installing the extractor spring, insert, and o-ring to turn th spring counter clockwise and remove old spring and insert and then install the new insert and the spring clockwise?


Oh thanks for the info on the pricing. Hey will you be able to capitalize on this..say make it a 'G&R accurized BM' and put a stamp some where on it for marketing purposes?

[Robb Jensen]

Question...where on the front sight post is the F mark found? Also, is the correct procedure for changing and installing the extractor spring, insert, and o-ring to turn th spring counter clockwise and remove old spring and insert and then install the new insert and the spring clockwise?


Oh thanks for the info on the pricing. Hey will you be able to capitalize on this..say make it a 'G&R accurized BM' and put a stamp some where on it for marketing purposes?

I'm not Grant but:
F marked FSBs will be marked on the left side of the FSB. (the shooters left side). I'm not understanding the 'clockwise' question. Extractor springs are installed biggest side toward the extractor, smaller side toward the bolt. The extractor spring and it's buffer should 'click' into the extractor.

[ksa464]

I just got through posting on the other topic, "O'h no, I just bought a Bushmaster" and saw this one.... I must repost what I said there since it really applies here too.

I am thinking seriously now about send my gas key to Grant! Here is my post:

I have to say that I love this post. I have a Colt M-16 A2 sporter (I have had for 18 years) and came across a good deal on a BM 14.5 M-4 Izzy. I shot the BM the first time out in Febuary to sight and function check......14 full 30 round mags (420 rounds) and 4 different brands of 55 gr. ammo. About 200 or so into the maiden run of this fun rifle, I had a double feed; an empty case with a live one wanting to come up the ramp. This was a fresh Remington green box round. (as opposed to Wolf which BTW functioned 100% thru 90 rounds).

Stunned, I said "I'm going to do a few Rob upgrades". My 2 brother-in-laws that were with me, 1 an absolute gun nut and the other a 12 year Army vet and very familuar with the M-16 both said "What! It's one failure in a break-in, its fine. Its probably just a bad round or magazine" I said "no way". "I will give this one more shake upon my next visit to the range, but if it fails then, I'm selling it". I own 2 GLOCKS that are 100% after a collective 4500 rounds, so I compare everything to GLOCK now. Anyway, I marked the supect mag with a marker and set it aside to try again next time.

Anyway, other than that we got it battle sighted (running stock iron sights) and produced a wonderful 3" round hole in the middle of the paper after it was all said and done. But I noticed that the next day my shoulder also had a bruise on it. Mind you, I probably only shot 200-250 rounds myself because my brother-in-laws were also shooting it and helping me sight it.

So off to the "Rob list" I went: H buffer and a crane black insert and O-ring from Bravo Company.....tossed in a few more mags and Gen II Magpul followers too (I think those green ones suck -they tilt too much for me)Installed the new buffer and upgraded extractor.

Fast foward to last month, my 2nd visit to the range with this rifle.... 15 full mags, 450 rounds now, 3 different 55 gr ammo; once re-loaded Lake City from a gun show, Tiawan PMC and another 90 rounds (3 full mags) of steel Wolf that all AR guys seem to hate. (Again, I'm a GLOCK guy, I feel that that firearm should eat everything). My point is, this is less than desirable ammo.

I'm by my self this time, so I will have to take all 450 rounds into my shoulder. How will I and the rifle fair this time? Remember, I will sell this POS if it fails again and I need to eleminate a possible bad magazine.

RESULT: AMAZING! 100% reliability, noticably less recoil and a nice tight pile of brass and steel about 8 feet from my 4 o'clock! The suspect mag which I intentionally loaded with the Wolf crap; 100%. The next day I did not feel a thing in my shoulder and NOT PHYSICAL SIGN on my body, i.e. bruise.

I attribute the wonderful function to the upgraded extractor (which I feel was the cause of the original double feed) and the H buffer (which I attribute to a comfortable shooting sesion - and maybe a slower bolt action) to a happy and trust-worthy rifle.

Thanks Rob! Its amazing what a $25 buffer and $3 extractor upgrade can do.

[BushmasterFanBoy]

Oh dear lord.

Grant wasn't joking.

Don't want to sound like I am making a personal attack, but I believe everyone here knows what type of product Bushmaster puts out. It simply isn't up to spec as yourself and others have pointed out in the past. I'm a little flabbergasted that you actually are buying Bushmaster rifles. I seriously thought it was an April fools joke. You've consistently stuck by the fact that Bushmaster products are not up to usable standards, and yet the forum now sees this.
Granted, you are attempting to improve the rifles, but since they are crap to begin with wouldn't it be better to just let the Bushmaster segment of the industry rot? (Until Bushmaster pulls their head out of their a** and starts making a proper weapon).

An excellent effort no doubt at trying to improve what they are producing, but it's still a Bushmaster, and unfortunately everyone here knows of the DESERVED, less than steller reputation of their rifles. Yes, the improvements are nice, but it's still a Bushmaster. You may have been better off simply buying a lightweight barrel and sticking it on a 6920.