AR15 experts - are these parts okay?


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oldguy870
August 9, 2011, 01:05 PM
I have a gun with several thousand rounds down the tube. I am wanting to do some preventative maintenance on the bolt. I was thinking about replacing:

1. Gas rings
2. Extractor
3. Extractor spring and black buffer
4. Extractor pin
5. Cam pin

I can order them online from Brownells. However, the extractor and extractor pin is DPMS. The gas rings are TTI. The cam pin is High Standard. The buffer is Brownells. And the spring is Colt.

For a gun you would trust your life to, would you be comfortable using the above list of components? How do I know if they are milspec?

I am guessing that only a few companies actually make these parts and most places you go would be selling the same part with a different name on it.

Any better suggestions on where to get these items?

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Mot45acp
August 9, 2011, 01:14 PM
try this
http://www.bravocompanyusa.com/BCM-SOPMOD-Bolt-Upgrade-Rebuild-Kit-p/bcm%20bolt%20upgrade%20kit.htm

They are out of stock on the cam pin though.

briansmithwins
August 9, 2011, 01:15 PM
All of those parts are replaced when they fail. I've never seen a .mil manual that called for them to be replaced at a certain round count.

When I owned ARs, I had a complete spare bolt* with firing pin and FPRP that I carried with me. Some of the small parts on the bolt are a pain to replace in the field w/o tools. I checked headspace on the spare bolt so I knew it was good on my rifles.

Some very good manuals here: http://www.biggerhammer.net/manuals/

I specifically recommend the 'M16A2 Marine Corps Rifle Manual'.

BSW

*ARs break bolts. They all go eventually.

snakeman
August 9, 2011, 01:15 PM
you could try midwayusa.com or galatiinternational.com also model1sales.com

briansmithwins
August 9, 2011, 01:32 PM
If it were me, I'd buy one of each:

http://www.bravocompanyusa.com/BCM-AR15-Bolt-Assembly-MPI-p/bcm%20bolt%20assemly%20mp.htm

http://www.bravocompanyusa.com/Firing-Pin-AR15-p/firing%20pin%20ar15.htm

http://www.bravocompanyusa.com/Retaining-Pin-for-Firing-Pin-AR15-p/retaining%20pin%20ar15.htm

Why pay shipping from 5 different places?

BSW

Z-Michigan
August 9, 2011, 01:41 PM
I would prefer not to use an extractor or cam pin made or sourced by DPMS. I would choose BCM parts if possible (Colt, Daniel Defense, and LMT would be equally good or possibly even better).

It's good to have spares on hand but I wouldn't replace those parts until they break or show obvious wear. The only one likely to show wear by now is the extractor spring.

taliv
August 9, 2011, 01:49 PM
i now swap out bolt and cam pin after 5-6k rounds because they start to develop cracks that can be difficult to see around that point. usually BCM parts
(not for game guns though... i'll just run those until they break)
replace the extractor when it feels dull. when you drag your finger across it, it should be sharp

never heard of an extractor pin failing.

replace the extractor spring and buffer when you can move the extractor with finger pressure.

Bartholomew Roberts
August 9, 2011, 02:29 PM
I use pretty much the same procedure taliv just outlined.

For gas rings, I extend the bolt from the bolt carrier with the cam pin removed and stand the carrier upright on the bolt face. If the bolt collapses completely, I replace the gas rings.

And like briansmithwins mentioned, I usually just keep a spare bolt handy rather than all the small component parts. It is faster to swap out and fixes most of the common wear items on an AR.

gotigers
August 9, 2011, 03:16 PM
for small parts another vendor is http://www.thecitizensarmory.com/catalog/9

HOLY DIVER
August 9, 2011, 06:02 PM
if it were me i'd buy 2 complete bolts from BCM,install 1 keep 1 for a spare
order a cam pin x2 ^^^^^^^^^^^
repeat process on the firing pin

Strykervet
August 9, 2011, 09:23 PM
Change the gas rings when the bolt and carrier assembled collapses when set on the bolt face. You have to be light though, because it will collapse when the rings are good if you don't set it down carefully. The point is that it should have enough friction to hold the carrier up on its own. Not that it won't work if it falls, it is just time to swap 'em out if you have 'em.

The extractor pin is fine unless it fits real loose.

The extractor is okay unless it is cracked or very worn. It needs sharp edges to work right. If the edges are very worn, replace it.

The extractor spring needs to be replaced after so many rounds. How many depends. I would replace it with one of those black rubber rings with the spring inside that if I were you. They work much better than the old spring with the little rubber knob inside, and don't wear out as fast.

The pin only needs to be replaced when it falls out or if it is bent and hard to put back in. This happens before it breaks usually.

I'd also get two of each and put half in the stock or grip, then replace what you need to and put the rest in your parts drawer.

Replacing the bolt is wholly unecessary. I'd only relpace that if it were cracked, broken, or worn considerably, such as in rounded lugs, etc.

Springs are what you need to worry about. Get extra springs. Midway has everything, as do most manufacturers. Call and ask if it is milspec if it doesn't say. If it is milspec, it really doesn't matter who made it. Milspec is milspec, materials and measurments.

Strykervet
August 9, 2011, 09:36 PM
While you are ordering this, throw in a firing pin too. They tend to get bent when you most need it.

What may actually be cheaper in the long run is to find parts kits. The small parts kits. That way you have detents when you lose them. DPMS makes fine parts. In fact, their trigger group is light years better than some, and I polish the engagement surfaces to get a 4.5lb. trigger that is very nice. Their springs are also the right springs --I can't recall who so I won't say, but some dealers sell springs that are definitely not in spec, and maybe not even AR parts.

Headspacing shouldn't be a problem on the AR. That has to do with your bolt ext. If headspacing is off, either that is worn or off or out of spec., or your bolt is out of spec. This is assuming the barrel is installed properly. I replaced barrels many times and never had a headspace issue. The only time I thought I had a headspace issue turned out to be that the chamber wasn't reamed.

kwelz
August 9, 2011, 09:49 PM
Avoid any DPMS parts. I suggest you look at BCM or DD parts.

Gandrtactical.com is a great source for these and others.

Z-Michigan
August 9, 2011, 09:53 PM
Call and ask if it is milspec if it doesn't say. If it is milspec, it really doesn't matter who made it. Milspec is milspec, materials and measurments.

The problem is that not everyone means the same thing when they say "milspec." It's an almost meaningless term unless you know who's saying it and what they mean - hence, meaningless. Companies like DPMS say milspec when they mean that it's basically the same size and will work in the application - rarely does it mean the same materials, treatments, and tolerances as a part that would be accepted by US government inspectors for the same application in a military M16 or M4.

Here's the short list of companies selling parts that truly meet military specifications in all ways:
Colt
BCM
LMT
Daniel Defense
G&R Tactical (not a manufacturer, just a dealer)

There are many quality companies that aren't on the list above, and their parts will probably work fine, but if you want parts that are at least military specification, stick to those.

Onmilo
August 9, 2011, 10:44 PM
Prairie River is a Mil-Spec O.E.M. manufacturer of small M16/AR15 parts.
Brownells works in partnership with Prairie River so rest assured, the parts you order marked as Brownells or Peairie River are indeed "Mil-Spec." HTH

madcratebuilder
August 10, 2011, 09:10 AM
Change the gas rings when the bolt and carrier assembled collapses when set on the bolt face. You have to be light though, because it will collapse when the rings are good if you don't set it down carefully. The point is that it should have enough friction to hold the carrier up on its own. Not that it won't work if it falls, it is just time to swap 'em out if you have 'em.

If you use that test method you well be replacing good rings. Down load and read the 23&P. This is how to test the gas rings.

Check for worn rings by holding the key and bolt
carrier assembly (3) with the bolt assembly facing down. If bolt assembly falls out after firing pin retaining pin (4) and
bolt cam pin (5) are removed, the rings are worn.


I have a gun with several thousand rounds down the tube. I am wanting to do some preventative maintenance on the bolt. I was thinking about
replacing:

I would keep those parts, and more on hand, but I would not replace them until PM indicated worn parts or you have a malfunction. If it's not broke, don't fix it.

oldguy870
August 10, 2011, 03:01 PM
I went to LMT and just bought a spare bolt. $66. It is MPI tested and has the black buffer. I think that is a good plan. I will just keep it in reserve until failure.

OhioChief
August 10, 2011, 11:57 PM
I keep a couple parts kits. I'm always fishing in there to find a pin or spring. Especially if you're building a lower and shoot a detent pin or spring across the room. The vacuum cleaner will find it before you will. I also like Midwayusa. They ship so fast it's almost there before you order.

Z-Michigan
August 11, 2011, 12:04 AM
I also like Midwayusa. They ship so fast it's almost there before you order.

Midway is good, but you should try AIM Surplus. I usually get stuff the next day, and I'm 300 miles away.

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