260 ackley or 260 terminator

[Bret GRAVELINE Graveline]

A 3/4 in factory M/R contour barrel, I'll take that barrel if you decide to give up on it, you didn't mention how much it opens up, A primer change at times can make a big difference, as can a bullet change, I once dealt with a Browning safari grade with a feather lite contour it would not hold a reliable inch group with 55 gr Nosler bt's but would put the 50 gr under 6 tenths and was a average of 4 5 shot groups, but if thats the bullet you want that make things difficult, how many rounds are thru this barrel I've dealt with guns that dramatically change its preference after 200 to 300 rounds, you mentioned its bedded, is the barrel bedded you could try putting a shim at the for end tip and put more upward pressure on the barrel, I fitted a mountain rifle stock to my standard 700 in 220 swift that shim has been in place nearly 20 point of impact never changes

 

[bsnyder]

It's opens u

A 3/4 in factory M/R contour barrel, I'll take that barrel if you decide to give up on it, you didn't mention how much it opens up, A primer change at times can make a big difference, as can a bullet change, I once dealt with a Browning safari grade with a feather lite contour it would not hold a reliable inch group with 55 gr Nosler bt's but would put the 50 gr under 6 tenths and was a average of 4 5 shot groups, but if thats the bullet you want that make things difficult, how many rounds are thru this barrel I've dealt with guns that dramatically change its preference after 200 to 300 rounds, you mentioned its bedded, is the barrel bedded you could try putting a shim at the for end tip and put more upward pressure on the barrel, I fitted a mountain rifle stock to my standard 700 in 220 swift that shim has been in place nearly 20 point of impact never chang

It opens up over an inch which doesn't work for me. As far as round count goes, I'm unsure as my father Inlaw gave me this rifle. I know I personally have 510 documented rounds down it.

 

[Bret GRAVELINE Graveline]

Well we can rule that out then, after 500+ rds it should have settled in, try the primer change you might be might be surprised, although I have guns where I can load 5 different primers with not much change, and I have a 25 06 that with a cci 200 primer igniting a charge of 56 grains of re22 shoots better than any bench rest or mag primer, and its not the only rifle I've found that, I'd give the upward pressure a shot 3/8 wide plastic playing card just might cure that, I'm serious about buying that barrel if can't find a cure.

 

[matt_3479]

That is very strange. I know my custom 260 rem is on the slower side but can still get too 2875fps range with superb accuracy before any issues.

if your doing an entire new barrel then I suggest sticking with the 260 as you already have brass and dies. Moving away from the 260 rem then unfortunately I have 0 experience with either the ai or terminator but bother are great rounds and my smiths recommend the ai highly! That said If you want to try something new all together and reuse your dies you could do something like a 25-260 and buy a new bushing if your dies are bushing dies. If not forget about

 

[Rosebud]

A 3/4 in factory M/R contour barrel, I'll take that barrel if you decide to give up on it, you didn't mention how much it opens up, A primer change at times can make a big difference, as can a bullet change, I once dealt with a Browning safari grade with a feather lite contour it would not hold a reliable inch group with 55 gr Nosler bt's but would put the 50 gr under 6 tenths and was a average of 4 5 shot groups, but if thats the bullet you want that make things difficult, how many rounds are thru this barrel I've dealt with guns that dramatically change its preference after 200 to 300 rounds, you mentioned its bedded, is the barrel bedded you could try putting a shim at the for end tip and put more upward pressure on the barrel, I fitted a mountain rifle stock to my standard 700 in 220 swift that shim has been in place nearly 20 point of impact never changes

Tried another chronographs, maybe you're faster than you think.

 

[bsnyder]

I used a magneto speed and a lab radar

 

[Rosebud]

I used a magneto speed and a lab radar

Then I have nothing else to add that the others have not already posted. That really sucks, my Grendel is faster than that.

 

[bsnyder]

Yup I think I will just rebarrel it to 260 ai

 

[Coyote Shadow Tracker]

I have (had) have four .260rem and shoot H4350 (around 42gr) SGK140, SMK142 , 123, 130TMK, 140SMK and get over 2700fps with all of them, They all shoot <1/4" groups.
We are currently build a 6.5X284 for "F" class, but not much more fps that the .260. We never look for fast fps only what small groups we get at the range we want. Accuracy is more important, but for hunters maybe more speed. Personal preference I guess.

 

[nkyshooter]

THAT slow is not "just" a slow barrel ... THAT slow is probably a bad chamber job causing pressures WAY earlier than you should be experiencing.

I shoot 260AI - my favorite "all around" rifle - I built it as a 'tactical hunter' and use it exactly as you describe - hunting/chucks/steel - it is my 2nd most accurate rifle after my 6mmBR - not really a fair comparison as the 260AI is a medium weight contour and the BR is a heavy varmint.

I get 2900+ (27" bbl) with berger 140 hunting vld's into about .4" 5 shot groups a 100 using (don't judge me) H414 and CCI BR4 in lapua brass (fireformed 260). There is more speed available with other powders but I don't need to go there so I shoot what I have that works.

I liked the suggestion to use the Tubbs solution - that can help to clean up a less than ideal factory washboard barrel ... but that much velocity lost almost has to be due to a wonky chamber. If it was mine, and I were thinking to go 260AI or Terminator (essentially just an AI with a bit gentler shoulder angle) anyway, I might just have the barrel re-chambered to the AI or Terminator and then use the Tubb system on the barrel while fireforming the brass to the new (and hopefully correct) chamber/cartridge.

Otherwise - new barrel - 260 vs 260AI vs 260 Terminator ... pick what you like/want - they all shoot AWESOME with the AI having the highest POTENTIAL velocity and the Terminator being a bit less finicky on the feeding.

 

[johnnyk]

Bought my son a Rem700 stainless Mtn rifle w/laminate stock, in June of 2004 and experienced a lot of consistency and accuracy problems. This was purchased strictly for the boy to deer hunt with. It had 22" pencil thin barrel and gave me a fit for about 4-5 months. A lovely, slick, little rifle but consecutive charges (i.e., 42.5, 43.0, 43.5) would go from 1.5" to 3" to 3/4". Drove me nuts!
I had purchased him the Ruger compact (18.5") barrel to start with and it was worse than the Remington and louder, to boot! It would have made a good gun for "kicking up" moose! 2.5-3.0" was the norm, no matter the component(s) combination.
So, I had high hopes for the Mtn rifle but my expectations and tolerances initially were too high. I found a good load with the 120gn Ballistic Tip, 46.5gn of H4350 and a Rem9 1/2 primer. It would print .374" for the first three and started scouring the county after than.
He really liked the little rifle, and kilt several deer with it, but "grew out of it" and got my .25-06Rem Sendero SF. I shot it for several years and a friend in Roanoke, Va had to have it.
My one word to describe the pencil thin barreled Mtn Rifles is; persnickety.

 

[bsnyder]

Bought my son a Rem700 stainless Mtn rifle w/laminate stock, in June of 2004 and experienced a lot of consistency and accuracy problems. This was purchased strictly for the boy to deer hunt with. It had 22" pencil thin barrel and gave me a fit for about 4-5 months. A lovely, slick, little rifle but consecutive charges (i.e., 42.5, 43.0, 43.5) would go from 1.5" to 3" to 3/4". Drove me nuts!
I had purchased him the Ruger compact (18.5") barrel to start with and it was worse than the Remington and louder, to boot! It would have made a good gun for "kicking up" moose! 2.5-3.0" was the norm, no matter the component(s) combination.
So, I had high hopes for the Mtn rifle but my expectations and tolerances initially were too high. I found a good load with the 120gn Ballistic Tip, 46.5gn of H4350 and a Rem9 1/2 primer. It would print .374" for the first three and started scouring the county after than.
He really liked the little rifle, and kilt several deer with it, but "grew out of it" and got my .25-06Rem Sendero SF. I shot it for several years and a friend in Roanoke, Va had to have it.
My one word to describe the pencil thin barreled Mtn Rifles is; persnickety.

Yup I believe we have the same rifle. It has always shot really accurate but slower than molasses running up hill in Maine in January. I've finally had enough and it's not like I don't have other options because I do, but I can't get rid of it as it was a gift from my father-in-law before my wife and I got married I think the rebarrel in 260 ai is in order and be done with it. I can get some Lupua brass to fire form and be done. Finally at a point in life where I can start making things that I want. Im heavy to begin with in the 6.5 cal realm as we have a 26 nosler 6.5-300 wby, 6.5 Sherman short and the 260. I just hate rifles that sit around and don't get shot or ones that don't shoot straight as I'm sure many of us here can relate too. I want to thank everyone for their input and advice.

 

[meatyrem]

I have tried n560,rl,26 H4350,6.5 staball,imr 4064, rl 16, this barrel just seems to loose its accuracy as soon as you get or 41 grains of pick your powder. That why I'm wanting to rebarrel and sense I'm at it I might as well pick a something new and different to play with. I know it's not the cartridge more than likely it's barrel and it's a 9 twist which does me no good with all the new fun Bullets out there. So I was thinking fresh start.

Maybe the twist is way wrong for the weight you're using. Just a thought