223 AI: expected barrel life & other questions

[capreppy]

I've got a Savage 1/9 223 Rem. I'm very seriously thinking about rebarreling to a CBI 1/8 223 AI. What is the typical barrel life of a 223 AI barrel?

My plan right now is to take loads that I currently run in my 1/9 and redo them. I currently run H322 w/Hornady 50gr Z-Max and Varget with Hornady 68 & 75gr HPBT. For those that run an AI, do you just tweak your current loads with the expectation that you'll run more powder and faster speeds?

 

[fnbrowning]

Barrel life is directly related to the composition of the barrel steel, and how that composition (stainless, chrome-moly) resists throat erosion. The throat erosion will be a factor of the powder type and how much velocity you are demanding; i.e. how much powder is fired.

Throat erosion is easily noticeable in large magnums much faster than smaller calibers. The Ackley Improved is not in this group. It is what, a shoulder bump for a little extra case capacity. Not a factor in throat erosion over the regular .233.

BTW: If you are worried about barrel wear, use the premium CM barrel of your choice, and have it nitrided. No accuracy loss and significantly extended life.

 

[capreppy]

Not terribly worried about barrel wear, but am curious as to how it relates to typical 223. As I understand it, typical 223 will last 5k (very rough numbers). All things being equal and similar loads, would I expect the AI to run around that? The barrel will be from CBI (Criterion Barrel) and will be in SS so nitriding isn't an option. I don't have an issue with buying another barrel if I am getting 5k in barrel life.

 

[fnbrowning]

Wear on a barrel is determined by:

1. The amount of powder burned (how many BTUs of heat are produced)
2. The diameter of the bore (what area in square inches is exposed to the heat)
3. The pressure of the load (higher pressure increases heat transfer)
4. The heat build up, at a match firing twenty rounds in 20 minutes gets a barrel good and hot.

Yes, you can nitride a stainless steel barrel. It's just that the effects are not as pronunced.

Chrome-moly is stronger in both yield strength and hardness. Stainless steel has a longer barrel life, and is more corrosive resistant. But all stainless steels benefits against CM become moot when the CM barrel is nitrided. Then the CM barrel life is significantly longer than the stainless barrel, and the barrel itself is far more corrosion resistant than stainless can be.
Since accuracy is a function of the manner of rifling and overall quality of the barrel itself, then when nitriding is factored in, there are no longer the traditional benefits of stainless over the chrome moly.
5000 rounds with a regular barrel? How would you like to double that with very little increase in cost??

 

[capreppy]

Can you nitride a barrel from the get go? I've read that you need to break the barrel in some before you nitride, basically smooth out the rifling. It the barrel has been hand lapped after rifling, do you still really need to break it in?

 

[Sterling Shooter]

Here's my experience, shooting in HP competition I expect a .223 barrel to get any of the first 3,000 rounds shot from it to the 600 yard X-ring. After 3,000 rounds, I expect my X count average will begin to fall. I usually rebarrel at about a 2500 round count. I sell my discarded barrels for one hundred dollars to a local guy who builds uppers for friends and family. My net expense for a barrel is about $250 for a barrel turned by Frank White. I've used both cut and buttoned rifled S.S. barrels from him over the last decade. It seems the Krieger cut rifled barrels last longer but the Douglas button rifled barrels are more accurate. That's the way it seems, but who knows. With the Douglas barrel I now have on my match conditioned AR Service Rifle, with irons and sling from prone, I recently shot a 198 with 17 X's on the MR-31 target. This suggests I have a very good barrel which allows for my talent to shine.

 

[fnbrowning]

Can you nitride a barrel from the get go? I've read that you need to break the barrel in some before you nitride, basically smooth out the rifling. It the barrel has been hand lapped after rifling, do you still really need to break it in?

Yes, you can nitride as a final production step without breakin. That's what the guys at superior barrels do. They start with a true match blank from Douglas. Have it profiled by one of the best match barrel makers,Compass Lake. Then it's nitrided before assembly.

You know the barrel breakin/no breakin is a whole can-o-worms, right?

 

[capreppy]

Barrel breakin is not one topic I wanted to discuss

I'll give some thought to having the barrel nitrided one it gets in. It'll be a special order barrel so I'm looking at 11 weeks or more before it is in.

 

[BoilerUP]

A Criterion barrel is $300 from Jim Briggs.

Over 5000 rounds (probably on the low side for a 223AI), that's $0.06 per round in barrel expense.

Even if you drop 15% barrel life from going 223 to 223AI, your per-round barrel expense is only 1 cent more.

BTW: my 223AI is a 1:7 Criterion...thing hammers with 80gr A-Max.

 

[capreppy]

BTW: my 223AI is a 1:7 Criterion...thing hammers with 80gr A-Max.

I considered a 1/7 twist, but others have stated not worth it unless you are going to be shooting a lot of 90gr VLD's. I thought about that and I coulnd't see the not worth it part.

With that being said, I've got a stock pile of 50gr Z-Max's, would these shoot ok out of a 1/7?

 

[cornhusker]

I always get stainless barrels,but I think I am going to get a regular barrel next time..Why?
It is my finding that a stainless takes longer to heat up and also LONGER to cool back down.

Only my dimes worth is all....john

 

[capreppy]

Another silly question. I can find 223 AI go gauges, but cannot find nogo gauges. What do y'all do when you can't find nogo gauges?

 

[shoot4fun]

Are you going to do the rechamber or just install on the Savage when done?
I believe the 223AI should headspace the same as the 223. After all, all you are really doing is blowing the taper out of the case.
Could be wrong and I am sure someone will tell me really quickly.

 

[BoilerUP]

Another silly question. I can find 223 AI go gauges, but cannot find nogo gauges. What do y'all do when you can't find nogo gauges?

Put 1 piece of Scotch-brand clear tape on the bottom of your Go gauge...you now have a No-Go gauge.

Done 5, maybe 6 barrel installs using this method...safe and easy.

 

[7mmRM]

My original 223AI has approx 6500 on it. I set it back at 4500. Its time for a new tube. Bbl is a 1-8 PacNor. Shot 75s @3050ish the whole time.

 

[capreppy]

Put 1 piece of Scotch-brand clear tape on the bottom of your Go gauge...you now have a No-Go gauge.

Done 5, maybe 6 barrel installs using this method...safe and easy.

I thought this might be the case. Thanks for the tip.

My original 223AI has approx 6500 on it. I set it back at 4500. Its time for a new tube. Bbl is a 1-8 PacNor. Shot 75s @3050ish the whole time.

Good data point. I'm hoping I can get 4k out of it before I need to rebarrel.