(Accuracy q NOT function) Do some barrels just not like certain ammo?

[Kwanger]

I just built a(nother!) AR, this time using a 1/8 twist polygonal rifled 16" stainless barrel. Took it out to the range for an extended test. Function is perfect with the different kinds of ammo I tried (Hornady Training 55gr and Brown Bear 55gr).

However - while the Hornady grouped incredibly well (close to MOA at 100 yards even with 10 round groups), the Brown Bear was absolutely terrible - I'm talking minute of 2ft NRA target at 100 yards.

I know from past experience that I can always expect the Brown Bear group to widen over the Hornady, because it just ain't that accurate - however, to go to minute of 2ft target as from this particular barrel seems bizarre. Several times switched back to the Hornady....and I was back to tight, consistent groups.

Does anyone have any idea what might be going on here? Its a new one on me.

 

[ol' scratch]

Yes, I do. Brown Bear is crap ammo AND your rifle doesn't like it. Some rifles can be picky about the ammo they like.

 

[Al Thompson]

Yes. Some barrels are very picky and some are not. Also, the individual lot of ammunition can vary quite a bit and throw things out of wack. I have a significant stock of a major ammo maker's product that shoots very well. Recently, I purchased another 500 rounds and it shoots like crap. The good stuff was purchased prior to 2008, so what ever changes they made was not good.....

 

[ironhead7544]

Some barrels will not shoot steel jackets. One maker tried shooting some into a recovery medium and found no rifling marks on the bullets. They thought the bullets just pushed their way through the barrel. The bullets just did not take the rifling.

 

[Kwanger]

Thanks for all the responses guys - guess this one just doesn't like Bear (it wasn't a bad batch of ammo either, as I tested it side by side with my Bear lovin' M&P15.

Ironhead - you may very well be onto something there, and I almost suspected the same thing myself - the mild steel in the bimetal jacket may not be playing well with the combination of polygonal rifling and extremely hard nitrided finish....

 

[Snakum]

Brown Bear hollow points in x39 have shot consistently awesome in every weapon I run them through. Even Bear FMJs in 308 have been pretty good. Wolf and Win WW and Rem UMC wouldn't shoot minute of barn door in my chrome-lined Rommys.

Just goes to show ya, every barrel/receiver is different. Sometimes it takes a bit of work to find what it likes. But "crap"? I think not. Thousands of folks would disagree.

 

[Maverick223]

Just goes to show ya, every barrel/receiver is different. Sometimes it takes a bit of work to find what it likes. But "crap"? I think not. Thousands of folks would disagree.

I agree, BB may not be premium ammo, but it has served me well and has a failure rate that is probably far less than some of the brass stuff as well as a price that puts most others to shame.

I'd bet on the polygonal rifling being the culprit, same as with cast bullets.

 

[Kwanger]

I completely agree with you guys, I'm a huge fan of Brown Bear, having purchased well over 10,000 rounds of it last year. Failure to feed, fire or eject is a non issue for me. While I don't expect near MOA accuracy from it, from my run of the mill M&P15 barrel, I can still hit an 8 inch plate at 100 yards from field positions at a rapid rate of fire every time....whereas this new barrel won't do anywhere near that, it is literqlly flinging those rounds.

The good thing is I have a 90 day money back guarantee. I'm on the fence with it. Shot a match today, it performed superbly with the Hornady training ammo, and is seriously consistent hot or cold, which is important to me for long range action rifle/ 3 gun stages, for which I wouldn't use Bear anyway.

On the other hand....I just don't like the fact that it seemingly just will not shoot with even any pretence of accuracy with bimetal jacket ammo (and I'll be trying some Wolf to double check that theory). I usually use Bear for the close in hoser stages and training for matches, but with this barrel I even wouldn't trust it for that. I'll give it some more thought and testing over the next month or so before making a decision.

 

[Snakum]

I've been pulling my hair out for two weeks because every bullet and charge and OAL I tried in my S308 turned it into a bullet hose. While Brown Bear FMJ and Silver Bear SPs (yes ... soft points) tightened it right up to the 2" mark every time, closer to 1.5" for the first four. Made absolutely no sense at all. But it was what it was. I finally found a load today that shoots in it.

There are no absolutes in accuracy, except that FGMM shoots well in everything if you can afford it. But outside of the FGMM phenomenon, you have to throw conventional wisdom out the window sometimes.

 

[Maverick223]

I'm not a competition shooter, and you know your shooting style better than I (i'd be a bit creepy if that weren't true now wouldn't it?), but I wouldn't let cheap ammo stop me from using an otherwise good barrel. If you reload, you can approach or match (depending upon how frugal you are) the cost of BB in .223Rem....if you don't, this is a good excuse to take up a new hobby (a rewarding one IMO).

 

[Sport45]

Some barrels will not shoot steel jackets. One maker tried shooting some into a recovery medium and found no rifling marks on the bullets. They thought the bullets just pushed their way through the barrel. The bullets just did not take the rifling.

That's a little hard to understand. Do you have a reference for this? I can't imagine a steel jacketed bullet not taking the barrel's rifling unless they were severely undersized.

 

[Maverick223]

That's a little hard to understand. Do you have a reference for this? I can't imagine a steel jacketed bullet not taking the barrel's rifling unless they were severely undersized.

Just speculating here, but my thoughts were that it might be just a little too hard (more a function of the super-thick jacket than the mild steel used) and was pushed straight though because it didn't have time to form into the rifling (polygonal rifling deforms the bullet rather than cutting grooves in it) before the pressure pushed it down the line. Never heard of the phenomenon, but it seems plausible to me.

 

[Deus Machina]

The thing is, rifling of any sort is smaller than the total diameter of the bullet at the lands (for traditional rifling) or flats (of polygonal) so time doesn't factor. A bullet has to take the rifling, or it doesn't move down the barrel.

I could see, perhaps, just being swaged undersized by it, but if there are no rifling marks, it's undersized or it's not working at all how a bullet is supposed to.

 

[Kwanger]

Interesting. I have just ordered up a real buffet of ammo to do some extended testing with the barrel (which is a Rainier Arms Select with nitrided finish, btw). I'll post the results. If it is only problematic with the one type, chances are I'll keep it (it is really a beautifully finished barrel too). But if it is going to be super picky, it'll have to go back and I'll get a more traditional White Oak Armament barrel or something. Reason I would like this one to work though is that according to theory at least, it should last a long time and stand up well to the rigors of 3 gun and other practical shooting type applications.

Maverick - yep, I really ought to be reloading with the amount I shoot - but I doubt that'll fly with the family, I spend too much time away at matches and building AR's as it is!

 

[Maverick223]

I could see, perhaps, just being swaged undersized by it, but if there are no rifling marks, it's undersized or it's not working at all how a bullet is supposed to.

That is pretty much my theory, and because it is polygonally rifled there wouldn't be conspicuous markings on the projectile if that occurred, it would (in all likelihood) just appear a bit smaller as it was "swaged" down the smaller bbl.

Maverick - yep, I really ought to be reloading with the amount I shoot - but I doubt that'll fly with the family, I spend too much time away at matches and building AR's as it is!

Naw, that just means that you have recruits to enlist for help loading!

As far as a suitable replacement (if you choose that route), I have had really good results out of Krieger cut rifled barrels.

 

[ball3006]

Yes....

my 243 will shoot nickle sized groups with 75 gr bullets. If I use 80 grain bullets the groups are the size of a paper plate......chris3

 

[Snakum]

To wring the most out of any platform reloading/handloading is a must, unless you can afford Federal Gold Medal Match or Black Hills Match or Hornady TAP. I like working up loads for rifles, but hate the drudgery of reloading once I have the barrel and receiver nailed. But alas ... it's that, or give up groceries to buy Federal or Black Hills.

 

[brnmuenchow]

Barrels can be very picky almost to a point of me losing my mind & hair, for ex. my Winchester model 70 (.270Win.) likes the Blackhills "Gold" Barnes Triple Shock loads, and not some of the Remington loads. It also likes a good portion of the Winchester & PPU loads, but not Sellier & Bellot loads. I swear sometimes it is like a child! It is however exetremly accurate with the right load so I couldn't stay mad at it for long.

 

[ironhead7544]

Concerning the steel jackets taking the rifling: check here under FAQ: superiorbarrels.com. I also found another barrel maker that tried it with a new barrel and had the same results. Couldnt find that one. I have an early CIA Tantal that has a .224 sized barrel, as measured by me. Also has six grooves, very shallow. Keyholes badly with the steel jacketed ammo. Very accurate with handloaded 75 gr .224 copper jacketed bullets. I was researching my problem rifle when I found the reference to the steel jackets in U.S. made barrels. I heard that CIA now has the correct .221 barrel with 4 grooves and deep rifling like the the original barrels.

 

[ironhead7544]

Snakum: Try Reloader 15 and the Speer 168 gr match bullet. Was very accurate in my S308. Russian ammo in a Russian rifle generally works pretty good.

 

[Kwanger]

Concerning the steel jackets taking the rifling: check here under FAQ: superiorbarrels.com. I also found another barrel maker that tried it with a new barrel and had the same results. Couldnt find that one. I have an early CIA Tantal that has a .224 sized barrel, as measured by me. Also has six grooves, very shallow. Keyholes badly with the steel jacketed ammo. Very accurate with handloaded 75 gr .224 copper jacketed bullets. I was researching my problem rifle when I found the reference to the steel jackets in U.S. made barrels. I heard that CIA now has the correct .221 barrel with 4 grooves and deep rifling like the the original barrels.

Thanks for that ironhead - very good find there. Here is the direct link so others can have a look quickly:

http://www.superiorbarrels.com/FAQs.htm#Will using steel bullets damage my barrel

 

[Offfhand]

Do some barrels just not like certain ammo?

Yes, of course they do, but ALL barrels like certain shooters better.

 

[Kwanger]

Do some barrels just not like certain ammo?

Yes, of course they do, but ALL barrels like certain shooters better.

...but when the same shooter can get a certain size group with the ammo in question out of a different barrel, repeatedly, on the same day, side by side - but it is all over the place with the new barrel, it is unlikely to be the shooter, is it? Thanks for the contribution.

 

[FC]

My AR shoots everything except Wnichester and Federal bulk well, it shoots Remington and Brown bear 62gr hp of all things the best. You can pretty much shoot as many of the Brown Bear into an inch at 100 yards as you want, the Remington group about half that size, federal bulk is good for about a 3.5 -5 inch group at 100 yards. My .308 shoots Federal very well but Winchester isn't even minute of barn!

 

[Sport45]

I wonder, if you sectioned one of the bullets shown in the superiorbarrels link would you find rifling marks in the lead core? Maybe the steel jacket springs back to it's original form once the bullet leaves the barrel. In that case, the bullet may well have a loose core and I can see accuracy problems from that.

I can't imagine a steel cased, lead core bullet swaging a barrel out like an egg passing through a snake. And that's about what would have to happen (at +/-2800 fps) for it to not "take" the rifling. I'll bet even the bullets that didn't have rifling marks were spinning when they left the barrel.

The Danish M2 ball I used to get for my M1 was some of the best shooting ammo I've run across. It was steel jacketed and shot very well. I never tried to recover a bullet for examination though.