View Full Version : CMT bolt mil-spec?
buckshot1220
02-11-09, 08:51
Seeing as how the market is goin' nuts and quality BCG's like LMT and BCM are impossible to get, I started looking for others. Found a few places that have CMT bolts in stock. Now I've heard that they are mil contract holders, so are they mil-spec MP tested? I'm sure someone here knows better than I.
BTW-I am upgrading a Bushy.
Thanks in advance.
Can you post a link? If so I'll check it out.
buckshot1220
02-11-09, 08:57
http://dynamicarmament.com/items/ar-15-mil-spec-parts/bolt-bolt-detail.htm
^Don't know how to make it hot, you'll have to cut/paste^
Thanks.
Wow they are like 15 minutes from the house. I seem to believe that it has been posted here before that CMT/ Stag stuff was MPI tested. Maybe it's on the chart.
I was just checking Rainier Arms and their website says that not all CMT bolts are MPI checked only some. If you want an MPI tested one then you have to specify. My guess is that CMT would also mark it as such. So I would call DA and ask if it has an MPI marking on it.
buckshot1220
02-11-09, 09:10
Hmm... CMT isn't on the chart but Stag is. If Stag uses CMT parts???(anyone know for sure?) than their bolt is no improvement over what I have (Bushy).
For that price, they can KEEP IT! :eek:
Prices on their other AR stuff is ridiculous too.
Seeing as how the market is goin' nuts and quality BCG's like LMT and BCM are impossible to get, I started looking for others. Found a few places that have CMT bolts in stock. Now I've heard that they are mil contract holders, so are they mil-spec MP tested? I'm sure someone here knows better than I.
BTW-I am upgrading a Bushy.
Thanks in advance.
They maybe batch MP tested, but are not HP'd. They also have the blue extractor insert and no Crane O-ring.
So do they follow the TDP? No. Are they are good bolt, I think so.
C4
http://dynamicarmament.com/items/ar-15-mil-spec-parts/bolt-bolt-detail.htm
^Don't know how to make it hot, you'll have to cut/paste^
Thanks.
That is way over priced (FYI).
C4
Hmm... CMT isn't on the chart but Stag is. If Stag uses CMT parts???(anyone know for sure?) than their bolt is no improvement over what I have (Bushy).
CMT = Stag.
C4
buckshot1220
02-11-09, 09:32
Grant,
Do you have anything of the sort (milspec) in stock? I just placed an order the other day with you (I took the open box Vickers AK sling n a few other goodies) and I looked around but couldn't find any bolts in stock...
Thanks.
Grant,
Do you have anything of the sort (milspec) in stock? I just placed an order the other day with you (I took the open box Vickers AK sling n a few other goodies) and I looked around but couldn't find any bolts in stock...
Thanks.
Not at this time.
C4
If you go to the Bravo Company website, and check out the bolt carrier section, you will find TWO different CMT bolt carrier groups that are advertised as "MPI" inspected. One of the CMT carrier groups is semi the other is auto.
I assume since Bravo Co. advertises them that way, it must be an accurate description. Check it out.
http://www.bravocompanyusa.com/CMT-M16-Auto-MPI-Bolt-Carrier-Group-p/bcg-cmt-mp-m16.htm
If you go to the Bravo Company website, and check out the bolt carrier section, you will find TWO different CMT bolt carrier groups that are advertised as "MPI" inspected. One of the CMT carrier groups is semi the other is auto.
I assume since Bravo Co. advertises them that way, it must be an accurate description. Check it out.
http://www.bravocompanyusa.com/CMT-M16-Auto-MPI-Bolt-Carrier-Group-p/bcg-cmt-mp-m16.htm
CMT goes back and forth between batch MPing and full on MPing so it is really hard to know.
Keep in mind that MPing is virtually worthless without HP testing.
C4
buckshot1220
02-17-09, 22:25
Sorry to bring back a "near-death thread," I just looked at my bolt while cleaning and noticed it was marked "CM." I am wondering if this is Continental Machine or if anyone has an idea where it came from?
Thanks.
As I recently found out myself, CM bolts are Continental Machine and tool.
As I recently found out myself, CM bolts are Continental Machine and tool.
CM = CMT (stag).
C4
Digging this thread back up from a search. I got 4 CMT MP bolts for spares a month or so ago and was kinda bummed to find out they have the blue insert for the extractor. Oh well, I've got a BCM upgrade kit and will pick up another one next order I place from them. I guess these bolts will be good to go then.
Anyone know who makes RRA's bolts? I got 3 of their BCG's a while back and found that they do have the black insert in the bolt but no o-ring. Just wondering who made them if anyone knows.
I was pleased to find the bolt in my Double Star BCG has the black extractor and the o-ring. Anyone know who makes their bolts or BCG's by any chance? Being that the CMT and RRA bolts I have dont have the black extractor and o-ring combo I dont know if it's safe to exclude them from the possible makers for DS BCG's - unless DS installed the o-ring themselves.
.........
Digging this thread back up from a search. I got 4 CMT MP bolts for spares a month or so ago and was kinda bummed to find out they have the blue insert for the extractor. Oh well, I've got a BCM upgrade kit and will pick up another one next order I place from them. I guess these bolts will be good to go then.
Anyone know who makes RRA's bolts? I got 3 of their BCG's a while back and found that they do have the black insert in the bolt but no o-ring. Just wondering who made them if anyone knows.
I was pleased to find the bolt in my Double Star BCG has the black extractor and the o-ring. Anyone know who makes their bolts or BCG's by any chance? Being that the CMT and RRA bolts I have dont have the black extractor and o-ring combo I dont know if it's safe to exclude them from the possible makers for DS BCG's - unless DS installed the o-ring themselves.
.........
The black extractor insert used by RRA (and others) is nothing more than a blue extractor (but in black). They are not the correct density (FYI).
C4
Blankwaffe
05-03-09, 21:25
Grant,
Ive a got a silly question for you to add to my list of silly questions.
What would cause a bolt to have a magnetic surface charge from the manufacturing process?
All the bolts I have that came from my most recently purchased new Armalite uppers has a magnetic surface charge to them.I mean that they will stick to the carriers if laid along side them.Would probably pick up nails as well.
Just curious if you had seen this before.
Grant,
Ive a got a silly question for you to add to my list of silly questions.
What would cause a bolt to have a magnetic surface charge from the manufacturing process?
All the bolts I have that came from my most recently purchased new Armalite uppers has a magnetic surface charge to them.I mean that they will stick to the carriers if laid along side them.Would probably pick up nails as well.
Just curious if you had seen this before.
Yikes! That is a new one on me.
This would cause me some concern as it might slow the bolt down enough to where it might cause a malfunction. I would contact the manufacturer.
C4
Yikes! That is a new one on me.
This would cause me some concern as it might slow the bolt down enough to where it might cause a malfunction. I would contact the manufacturer.
C4
It's a new feature to help extract stuck WOLF steel cases from the chamber!! :p
(I'm sorry, but I couldn't pass on that one!)
It's a new feature to help extract stuck WOLF steel cases from the chamber!! :p
(I'm sorry, but I couldn't pass on that one!)
Hey, that is a fantastic idea! :eek:
C4
kalikraven
05-04-09, 11:07
It may be caused from a MPI test.
It may be caused from a MPI test.
None of the other MP tested bolts I have in the shop do it.
C4
I've had a couple bolts over the years that had a very weak magnetic charge to them. Enough to pick up a firing pin or other small things. After being used for a while they lost their magnetic charm. Caused no issues, and actually made it convenient that all the small BCG would stick together, but it didn't last long.
I only thought it was neat, in the most nerdy of ways.
dookie1481
05-04-09, 11:33
Prolonged exposure to a magnetic field would do it.
Jay
Jerz_subbie
05-04-09, 15:03
It could be something very simple, like poor packaging during shipping.
Same as when you strike 2 screwdrivers together and becomes magnetically charged.
Blankwaffe
05-04-09, 16:52
Yikes! That is a new one on me.
This would cause me some concern as it might slow the bolt down enough to where it might cause a malfunction. I would contact the manufacturer.
C4
Naw Im not worried about it enough to call Armalite about it.They probably think Im nuts already.I just wanted to know if you had ever seen it before.Its pretty strange though.
Regardless I have the Armalite BCG's in reserve to use as spares anyway since Im using LMT BCG's in all the Armalite uppers.So its even less of an issue.
Blankwaffe
05-04-09, 16:55
It's a new feature to help extract stuck WOLF steel cases from the chamber!! :p
(I'm sorry, but I couldn't pass on that one!)
Yeap...Rob needs to put that on the chart.......:p
I emailed Stag a couple weeks back to inquire about their backlog on carriers and bolts... A next day reply stated that they are 8 to 12 Months backlogged. Hope nothing I own breaks. Cause it will just sit and I will move on to the next gun. Just am Not going to throw away $$.
H
MP testing involves magnetizing the workpiece so that tiny magnetic particles find their way into any cracks. The particles make the cracks glow under a UV light.
After testing, the parts should be de-magnetized. In this case, it's possible that they didn't go through the de-magnetizer, or that they went through too fast and didn't get completely demagnetized.
Call a local machine shop and see if they have a de-magnetizer. It would only take a few moments to do the job, if they are willing.
As far as 100% MPI test versus batch testing goes, 100% testing is a Mil-Spec requirement. However, Mil-Spec requirements often place an inordinate emphasis on inspection and less on process control techniques that remove variation and ensure stable processes that produce consistent parts. Relying on 100% inspection is basically an admission that you have so much process variation that you cannot ensure quality unless everything is inspected.
So, do you want a BCG from a company that has to inspect everything, or a company that has sufficient process controls that they don't need to inspect everything? Inspection adds costs, but cannot create quality, only process controls can create quality.
That's the manufacturing engineer in me speaking, and that line of reasoning is appropriate for the machining of commercial products. For military use, since soldiers lives are on the line, 100% testing is appropriate because we can't allow any failures. I am curious how many bolts are rejected during MP test at the various vendors, though.
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