Fast Twist Barrel life in overbore varmint caliber.

[joshua]

I have read about and seen rifles at the range chambered for fast twist 22-250 in standard or AI format. Barrel twist must be at least 1x8 prior to even thinking about using 77 grain and up VLD/match bullets. I also suspect the barrel life to be short, but I would like to get some inputs of barrel life from owners of fast twist 22-250s or similarly behaved wildcats such as 243 AI fast twist, 6-284 and 6.5-284 shooting heavy match bullets requiring fast twist rifling. Merry Christmas! josh

 

[Jimro]

Under 4K rounds maybe half that depending on barrel manufacturer and stainless vs chrome moly and how tight the chamber/throat are.

4K is the "rebarrel date" for the AMU's match m16's, so you know the 22-250 will be worse.

Jimro

 

[joshua]

Hmmm.. do I really want a rifle that will need a new barrel every 2K rounds or less? It's all about how much I need it and if I have the bank to do it. Thanks for the input. josh

 

[Jimro]

For a really fun varminter build yourself a heavy barreled AR with a chrome lined barrel. There are different schools of thoughts on how chrome lining affects accuracy, but it will normally at least double barrel life.

A 1:8 twist is preferred for the 77 grain SMK's, but there is at least one company putting out a chrome lined 1:9 heavy barrel, which is fine for 69 grainers, possibly 75 grainers.

OR buy a Savage and the tools so that you can rebarrel yourself.

Jimro

 

[joshua]

I have a stock Colt H-Bar with a 1-7 twist barrel and it shoots very accurately, it will do 1 or less moa all day with SMK 77 grains. Also included in my inventory are Rem 700 PSS in 308 and Win 70 HBV in 22-250. I've been thinking if the extra FPS is actually worth all the hassle in getting a fast twist 22-250. A .224 bullet weighing 77 grains traveling at 3100 fps will reach out to 1000 yards great, it's the barrel life that is putting a stop to it. Maybe if Savage will bring out their LRPV in a fast twist 22-250 then I will get one, or maybe someone already started wildcatting the 6.5 Grendel like a 22-6.5 Grendel that will work great in an AR-15 platform. I thing the 25 wSSM in an AR-15 will be the ticket, but it goes back to the subject of barrel life. josh

 

[Jim Watson]

Jimro is right... at the end. If you want to fool with such stuff, put it on a Savage so you can change out barrels yourself.

I have tried to make an AR into a Long Range rifle with 6.5 twist barrel specifically for 90 grain bullets and it shoots very well. But when it is gone, it is gone and will have to go back to the shop for a new barrel.
My Savage .308 will be a DIY change or replacement proposition.

I shoot F-T/R class with those but see the guys in F-Open with their 6mm to .300 magnum rifles. The U.S. team and a lot of others use 6.5x284. They expect a barrel life of 1000 - 1400 shots.
I saw a guy bring a .308 with a documented 4700 shots to a match. He knew it was worn out but was trying to get one more day out of it. He could not hit the 6-foot backer at 1000 yards.

If you want a heavy bullet .22-250 you are going to have to pay the fare.

 

[U.S.SFC_RET]

Joshua I don't know anything about long distance shooting but how tight a group can someone shoot a .224 round weighing 77 grains at a thousand yards and what kind of platform is he shooting with?

 

[joshua]

I think it was Layne Simpson that had an article about the fast twist 22s. The rifle he used was a 22-243. If I remember correctly he had a 6" group at 1000 yards using the heavy bullets in .223 and it was fired in a heavy barreled remchester. I'm just trying to see if the advantages outweights the disadvantages which is barrel life. When a barrel replacement can cost anywhere from $350 to $500 and with the life expectancy of 2K, I may just stick with my 308 or I can always buy or rebarrel to a .260 Rem. josh

 

[U.S.SFC_RET]

260 Remington is a cotton pickin good cartridge from what I hear. I would love to try one out for a day or two. Remington has been known to put out some very accurate cartridges. Shooting 5.56 in the Army and watching them blow about in the wind just raises my curiosity. Layne Simpson must have been a meteorologist at ground level, perfect temp, humidity, any gusts at all, cold spots, out to a thousand yards, cool spots, mirages, temperature of the barrel, sunlight on the barrel ect..

 

[Ken O]

Barrel life comments

Jimro, I also agree with the Savage, I built up a .260 Rem on a Savage acton for the 1000 yard line, and have shot it at 600 also, but normally shoot the AR at 600.
I don't know where you got the 4000 rounds for the AMU, I have been squaded at Perry with most the members of the team at one time or another, and that question always comes up. It seems 2000 is more close to the magic number. My barrels ususally go between 3500 and 4000, there is no question when you get the off-call shots at 600, even though you clean the short lines at 2 and 300 yards. I usually shoot button rifled barrels (PacNor and Wilson) that are known not to have the life of a cut rifled barrel. I have a Krieger cut rifled upper ready to go to see when I shoot out the Wilson I am on now.
The shooters that I know that shoot the 22-250 get less than 2000 rounds. A top rated F-Class shooter I shoot with, uses the 6.5X284 and won't go to a big match with more than 500 rounds on it and he uses Kriegers. That round (as is the 22-250) are real barrel burners. The 6.5X284 is probably the most popular long range round right now, but the 6XC is creeping up.
If you want the best barrel life, shoot a .308, which will probably be my next project to shoot Palma.

 

[joshua]

I'm starting to like the Savage 12, but I'm mostly in it for varmints and slow fire long range target shooting. I'll wait for the Savage to come out with the LRPV in 260Rem. I wanted to shoot competitively in rifle matches, but it is way more expensive than say USPSA pistol matches. I love watching the steel plates being rang from 600 yards away. I have shot one club level match using my H-Bar, but the 600 yard steel plates were very humbling. I can read all the trajectory and wind drift tables, but it is still a matter of identifying the conditions through what your eyes see. josh

 

[MP-5]

I think the Savage 12 with their barrel nut design is "the move."

 

[JohnKSa]

Shooting 5.56 in the Army and watching them blow about in the wind just raises my curiosity. Layne Simpson must have been a meteorologist at ground level, perfect temp, humidity, any gusts at all, cold spots, out to a thousand yards, cool spots, mirages, temperature of the barrel, sunlight on the barrel ect..

If you were using a 55gr issue round, it's a completely different animal from the 77gr rounds.

For comparison, if you increased a .308 round's weight by a similar amount, it would weigh 210 grains.

The 77gr 5.56 rounds are more like short spears than typical bullets. They're very aerodynamic and therefore very wind-resistant.

 

[Buckythebrewer]

BC,BC,BC,Like mentioned,It is all about the bullet design,Not the weight.Because it is heavier does not mean it will cut through the air better.A good example is how well the 5.45x39 AK74 round makes the heavier AK47 round look completely useless for accuracy..The difference between the 2 is dramatic,,Not only in looks,but also in performance on targets 300+yrds..It is the same comparing 223 to 308.It takes a LONG and HEAVY 308 to spank a 223 in an ar15.And those bullets /and loads are not kind to the semi-auto actions to drive them up to speed..
Joshua, If your bullets and load are good(as well as barrel and rifle tweaks),And for ME using a scope.It does not take much to hit M.O.A. or better @ 600yrds..I was using 77gr smk with little effort at that range using 23.8gr h4895,winchester primers,.010 off the lands.I had no wind flags and the wind was mild when I shot so that might have helped alot..I believe the REAL challenge comes beyond 600yrds when things start slowing down.I did my shooting at a pit hitting a steel gong a made.I used 8X as well as 32X with no problems.I don't think I would do nearly as well with open sights.
Were you using a scope??Was the paralex adjusted out??That can be a killer
I just think the longer ranges beyond 600yrds is were the work is going to get harder.JMO

 

[garryc]

When it comes to barrel life nothing is better than a simple 4x5 card taped to your stock. That card has turret settings. I have three loads for my 22-250. A 50gr nosler BT at full power, A 50gr V-MAX at 223 level and a 45gr winchester at hornet level. I simply set my turrets for that load. Of course your scope must shoot the box dead on the money. My sightron s2's do that. In a field that is 250yrds across there is no need for 4100fps.

 

[Jim Watson]

Don't fall in love with the 77 grain bullet. That one is a special purpose item with nose and tail shapes to allow loading to .223 magazine length. Meant for NRA rapid fire stages and later adapted to shooting Afghans.

A 75 gr Hornady, especially the A-Max, or 80 gr Sierra or Nosler will have higher ballistic coefficient and do better at long range if you don't mind single loading, as for NRA 600 yd slowfire. Assuming one of them is equally accurate in YOUR rifle.

 

[Jimro]

Ken O,

the 4k round count comes from an instructor at the AMU when I went through the SDM course. These were the precision rifles that the school used for teaching, not the match rifles that the rifle team used. The accuracy standard for the student rifles was 1 MOA or less, hence the 4k round count.

Jimro

 

[joshua]

Joshua, If your bullets and load are good(as well as barrel and rifle tweaks),And for ME using a scope.It does not take much to hit M.O.A. or better @ 600yrds

I was also using 77SMK shot through my Colt H-Bar 1-7 twist factory barrel. No wind flags but if you have a spotter available he/she can be utilized. I didn't have a spotter except for the 2.5x10 Simmons scope on my Colt and being a newbie didn't really know too many folks, the guy that invited me did not show up that day. It wasn't the scope as it proved dead on at 100 and 200 yards. I didn't know if I had to adjust horizontally or vertically because I just did not see the bullets hit anywhere. Inexperience in my part I suppose, but I know some of the experienced shooters were laughing at me seeing how flustered I was. josh

 

[Buckythebrewer]

Joshua,At those ranges I noticed the best thing to do is not chase POI.I just got it near and winged it from there.1/8 clicks @100 yards add up to much more at those ranges.I just let the variables play there game and just kept aiming at the same point..