I posted this in another forum, but got no responses. I think the M4 forum crowd is more sophisicated and may have an answer.
The other day I ordered my new Krieger stainless barrel. While talking to the representative on the other line we were comparing the different types of barrels available. She stated that the cut rifled stainless barrels lasted longer than the button cut stainless and chrome moly barrels. Her rationale was that the rifling on a cut rifled barrel is higher than on a button rifled barrel. Her and her company have had a lot of experience with barrels and barrel making. In fact she was trying to steer me away from Krieger but I bought the Krieger anyway due to its great reputation.
Keeping all other factors the same such as round count and rapid vs. slow fire, will a cut rifled stainless barrel outlast a button riled stainless or chrome moly barrel?
Please no comments on chrome lined barrels, I know they are supposed to last the longest.
In my experience the people I know who use Krieger barrels are all Hi-Power/Service rifle shooters. These shooters replace their barrels about every 2K rounds. This is because the throat is too shot out for them. The barrels still headspace just fine. The barrels can be shortened to 10.3-10.5" barrels and rethreaded and the gas port opened up too work.
99% of the shooters in the world will wear out a throat long before the rifling is worn out. Also stainless barrels typically last 1/2 as long a chrome lined barrels for wear, but typically the stainless barrel is more accurate than the chrome lined barrel. However most shooters can’t shoot a chrome lined barrel to it’s full potential anyway so it’s typically not a problem.
Yeah I have throat erosion on my 1/9 chrome lined bushmaster so I started looking for a new barrel after about 7K rounds. 4 inches at 100 yards on sandbags. I was doing alot of rapid fire though early on in the barrel’s life. Young dumb and you know what.
She’s telling me that the barrel is good for about 7K rounds and that is slow aimed fire before groups start to open up. The button rifled chrome moly and stainless are lasting about 3K and 5K. Is that realistic?
Cut rifled barrels generally last a High Power shooter 6 to 6.5K before the X count really drops off. This is a trend that is prevalent with cut rifling. YMMV
According to the rules of this forum, we are supposed to only report fact, but I do have a theory on this. This is my opinion:
When a button is pulled through a barrel, the button actually swages the steel. It is the wierdest thing, you can feel the button go through the barrel if you wrap your hand around the barrel during buttoning. It is like a snake swallowing an egg.
My theory is, during the pressure and heat of firing, the steel is flexed, and relieves itself of these stresses. It may work harden, or just be weakened so the steel is not as erosion resistant, I really don’t know. My theory is born out by trying to set a chrome-moly barrel back, the steel in the throat area is work hardened, or flame hardened, and like as not you’ll chip the chambering reamer.
A cut rifled barrel doesn’t have any stresses induced into the steel during rifling. The cutter just simply cuts the steel, inducing no stress. You still will chip a reamer in this chrome moly barrel, but at least there is no stress from rifling.
I’ve been visiting this forum for a while, it seems to be made up of 3-gun shooters, and people who train at a Vickers or Pat Rogers class. Round count out of the guns is high. A premium is put on longevity and reliability. A Krieger barrel is a high example of the barrel makers art. In my own mind, I’m not sure if 3-gun or training is a proper application of a Krieger.
I shoot Service Rifle, so I want and appreciate a Krieger. I also want 100% reliability. Shooting an alibi sucks, and you become “that guy”. If you attend a training class, and shoot 1500 rounds, that’s 25% of the barrel life of a Krieger. IMO, you would be better served with a chrome plated bore that you could expect to get 12K to 15K out of. Just my opinion.
In high power, a chrome plated bore won’t let you be competitive. Shoot one at 600 yards and we can talk over beer and pretzels, I’ll buy, you can cry in the beer.
The cut rifled barrel will be the most accurate the longest. They take a long time to make and many of the rifling machines in service were produced in WWII. Almost all serious centerfire rifle competitors (benchrest, service, and long-range) will use a cut-rifled barrel.
The other three manufacturing techniques are for mass-production.
Hammer-forge machines can spit out a barrel in about three minutes. They’re great, big, noisy, and expensive machines but the barrels they produce are fairly good, dependent on the actual barrel alloy and proper stress relief. Because the machines are so huge and expensive big outfits make hammer-forged barrels. A Precision Shooting author asked Ruger for a couple of hammer-forged .22 centerfire (Mini-14) blanks and he chambered and matched them to AR service rifle uppers. He reported they were very accurate and would have made satisfactory, competitive Camp Perry-class rifles).
Button rifling is a fairly good technique and also makes barrels quickly (in comparison to a cut-rifled barrel). Pistol barrels are mostly broach-rifled.
A quality chro-moly barrel will give good, long service and its accuracy will drop off slowly. A stainless barrel will give great service and then one day you’ll notice your gun groups like dog poo.
If you’re shooting mostly 50 yards at AR blasto double and triple-tap 30-round mag rates of fire then you should be fairly happy with either mass-produced hammer-forged or cut-rifle barrels. If you’re going to Camp Perry you’ll want a cut-rifled or name-brand button-rifled tube.
Dont forget to mention the 600yd groups go to poo, with the same gun that cleaned 300 on the same day. As the throat burns out, you lose the longer distance accuracy. The 8 ring barrel at 600yds, will still be 10 ring barrel at 200yds for several thousand rounds more.
I was sort of surprised to see this discussion on an M4 related thread…in the precision rifle section perhaps, but as it relates to a relatively short barreled AR platform carbine I’d be surprised to notice any diffeence at all between cut and button rifled barrels.
Even amongst the benchrest crowd, there doesn’t seem to be a clear winner in the button vs. cut rifling debate. I have seen both give outstanding accuracy. I’m not sure either is necessary for “typical” M4 applications.
With that said though, as was mentioned above, throat errosion seems to be the limiting factor for barrel life, so the discussion of whether cut vs. button rifled barrels have longer barrel life seems irrelevant, since the chamber would reamed in the same manner in either case.
