.223 Chambered Oly Arms

[Impact]

I have a pretty old oly arms barrel..around 4,000 rounds of mil ammo through it ( full auto) and no prb. Knock on wood. lol..

[Iraqgunz]

Unfortunately I live in an imperfect world so a chamber cast isn't in my future. Having said that this ammo worked very well in the Colt barreled upper, and the 3other MILSPEC 1/7 twist barrels that I was able to use for testing. Again, of those carbines that had issues almost all of the problems were solved when using the reamer.

I have since taken the Bushamster upper off of my gun and replaced it with the Colt barreled upper I put together. In reality we shouldn't be having to do any of this had the weapon(s) been made to standards.

On a side note. I spoke with an acquaintance of mine who helped broker the deal with BM and the Georgian military. The feedback that he has received was less than stellar and I got the feeling that they regret the purchase.

If using Ned's throating reamer, you are probably aware that it is machined to dimensions more generous than standard 5.56 NATO dimensions. So it wouldn't surprise me if you used one on a NATO chamber that was in spec, you'd still remove some material. But if using a full-chamber NATO reamer, I really don't have any insight how much, if any, additional material might be removed from an "in-spec" NATO chamber.

I ain't no expert, but I believe a chamber cast is the way to go to understand what you're dealng with. In a perfect world we'd have a chamber cast made of the "as manufactured chamber", then ream it and note the amount of material removed, then a second chamber cast to see where you end up in the end.

I'll concede that the pic that Grant posted certainly suggests a significant amount of material was removed, but you still don't know from where: the shoulder, the neck, and the throat, just the neck and throat? That's the beauty of the cast, it lets you know where critical shoulder diameter, neck diameter, freebore diameter dimensions run, and gives you a visual of the throat length so you have an informed understanding of if you have a .223 style throat or a 5.56 style throat. And if you made enough casts, pretty soon you'd have a good ability to be able to correlate the amount of material removed to predicting how tight things were before reaming.

If you have the opportunity you might try taking some chamber casts of your BM's in your posession and see where you stand. It would be interesting to get some good data to see if indeed BM's are manufactured closer to .223 SAAMI specs or closer to 5.56 NATO specs.

[bkb0000]

Unfortunately I live in an imperfect world so a chamber cast isn't in my future. Having said that this ammo worked very well in the Colt barreled upper, and the 3other MILSPEC 1/7 twist barrels that I was able to use for testing. Again, of those carbines that had issues almost all of the problems were solved when using the reamer.

I have since taken the Bushamster upper off of my gun and replaced it with the Colt barreled upper I put together. In reality we shouldn't be having to do any of this had the weapon(s) been made to standards.

On a side note. I spoke with an acquaintance of mine who helped broker the deal with BM and the Georgian military. The feedback that he has received was less than stellar and I got the feeling that they regret the purchase.

I've noticed you mention your organization uses BM's before, and somehow have never bothered to ask- what happened? you work for a PMC, right? how was it ever decided that bushies were the right choice?

[Iraqgunz]

The laws of supply and demand along with bean counters who want to save money and think that a carbine, is a carbine is a carbine. The gov't only supplies weapons on certain contracts. Otherwise the contractor has to do it. Prior to these BM's arriving we used AK's, RPK's, RPD's, etc...

Try being a non-Gov't entity purchasing a few hundred M4's from Colt. Not going to happen. So someone put together a "package" and sold it as these are the next best thing, blah, blah, blah and this is what you end up with.

It doesn't happen now for the most part as we have people on the ground with knowledge and the recommendations from here carry weight in the rear.

I've noticed you mention your organization uses BM's before, and somehow have never bothered to ask- what happened? you work for a PMC, right? how was it ever decided that bushies were the right choice?

[Dave L.]

Grant,
So when will you post the Oly Arms Pre-order thread, I need 10

[Iraqgunz]

You'll need 10 just to get enough good parts together to build one that will work half way right.

Grant,
So when will you post the Oly Arms Pre-order thread, I need 10

[jmart]

Unfortunately I live in an imperfect world so a chamber cast isn't in my future. Having said that this ammo worked very well in the Colt barreled upper, and the 3other MILSPEC 1/7 twist barrels that I was able to use for testing. Again, of those carbines that had issues almost all of the problems were solved when using the reamer.
I have since taken the Bushamster upper off of my gun and replaced it with the Colt barreled upper I put together. In reality we shouldn't be having to do any of this had the weapon(s) been made to standards.

On a side note. I spoke with an acquaintance of mine who helped broker the deal with BM and the Georgian military. The feedback that he has received was less than stellar and I got the feeling that they regret the purchase.

What issues remained? Were you still getting popped primers? If so, to what remaining manufacturing defect would you attribute that to, given by that point you ensured your chamber was reamed to NATO spec?

[C4IGrant]

If using Ned's throating reamer, you are probably aware that it is machined to dimensions more generous than standard 5.56 NATO dimensions. So it wouldn't surprise me if you used one on a NATO chamber that was in spec, you'd still remove some material. But if using a full-chamber NATO reamer, I really don't have any insight how much, if any, additional material might be removed from an "in-spec" NATO chamber.

I ain't no expert, but I believe a chamber cast is the way to go to understand what you're dealng with. In a perfect world we'd have a chamber cast made of the "as manufactured chamber", then ream it and note the amount of material removed, then a second chamber cast to see where you end up in the end.

I'll concede that the pic that Grant posted certainly suggests a significant amount of material was removed, but you still don't know from where: the shoulder, the neck, and the throat, just the neck and throat? That's the beauty of the cast, it lets you know where critical shoulder diameter, neck diameter, freebore diameter dimensions run, and gives you a visual of the throat length so you have an informed understanding of if you have a .223 style throat or a 5.56 style throat. And if you made enough casts, pretty soon you'd have a good ability to be able to correlate the amount of material removed to predicting how tight things were before reaming.

If you have the opportunity you might try taking some chamber casts of your BM's in your posession and see where you stand. It would be interesting to get some good data to see if indeed BM's are manufactured closer to .223 SAAMI specs or closer to 5.56 NATO specs.

Couple things. My reamer from Ned is not oversized as I have reamed Colt, LMT and BCM and gotten ZERO material back.

Where the reamer removes material from will tell you a lot about where the issue is in the barrel.


C4

[jmart]

This is pulled straight from Ned's website, and it shows the deltas between sectioned SAAMI chambers, NATO chambers and a chamber reamed with his throating reamer. As you can see, the pic of his chamber shows additional material removed compared to the previous NATO chamber.



Link to a larger picture showing greater detail


Also, from the text on his website:

This reamer is designed as an easy, quick and sure way to know. You just open the upper receiver, remove the bolt group, drop in the reamer with some oil, and slowly turn it in (clockwise only, never reversing it), using a lot of turns and very little pressure. The handle centers itself in the upper receiver. When ithe reamer bottoms out on the chamber's shoulder it will spin freely-- it has stopped cutting and you are done. When you have done this, you know for sure you have a chamber with proper 5.56-plus dimensions in the critical freebore and throat area. Primer popping due to pressure spikes in a short leade will cease, but be advised there can be other factors in popped primers such as hot ammo, hot chambers, and improperly loaded ammo.

I'm wondering if some manufacturers have figured out along the way that the way to go is with a "plus-dimensioned" NATO chamber from the start. Maybe Colt and LMT are producing NATO chambers on "the high side" straight from the factory, and that's why you're not getting any material removal.

[Iraqgunz]

We still had an occasional popped primer as well as a cases that would stick in the chamber. Basically Bushmasters are crap and they cut corners and sell a product that they claim is a good as the next guys and they clearly are not.

Bottom line is I should not have to ream a chamber to make it fire ammunition that has worked in other 5.56 MILSPEC uppers, as well as the Bulgarian 5.56 AK's that we have.

I also agree with Grant in that I also put the reamer in the other MISLPEC guns to see what would happen and basically took crumbs out (almost nothing at all). WhenI put it into a new carbine that I had I got a lot of resistance for the first 4-6 revolutions.

What issues remained? Were you still getting popped primers? If so, to what remaining manufacturing defect would you attribute that to, given by that point you ensured your chamber was reamed to NATO spec?