bigpete wrote:Gday all,just keen to hear some experiences and feed back on using a 1:8 twist barrel on a 22-250. I'm planning to rebarrel my 22-250 soon with one,I'd like to run a bit heavier projectiles than what I am at the moment. Currently anything I try over 55gn shoots like utter ******,mind you,I'm also thinking the barrel is possibly on its way out anyway. It was my late best mates and I've no idea how many rounds he put through it before he passed away,all I know is its 20 years old,I've had it for about 5 years,and I've probably put close to a thousand through it myself. So if anyone has the same potential set up I'd like to hear about it. Also,the gunsmith I spoke to today didn't seem that keen on a 1:8 twist barrel,he reckoned 1:10,so I'm also kinda wondering why that might be. I hopefully intend to use 70gn speer projectiles in it a lot,or either 64gn PowerPoint's or 65gn sierra gamekings. I just can't see why 1:8 would be so terribly bad to be honest. Cheers,Pete
bladeracer wrote:bigpete wrote:Gday all,just keen to hear some experiences and feed back on using a 1:8 twist barrel on a 22-250. I'm planning to rebarrel my 22-250 soon with one,I'd like to run a bit heavier projectiles than what I am at the moment. Currently anything I try over 55gn shoots like utter ******,mind you,I'm also thinking the barrel is possibly on its way out anyway. It was my late best mates and I've no idea how many rounds he put through it before he passed away,all I know is its 20 years old,I've had it for about 5 years,and I've probably put close to a thousand through it myself. So if anyone has the same potential set up I'd like to hear about it. Also,the gunsmith I spoke to today didn't seem that keen on a 1:8 twist barrel,he reckoned 1:10,so I'm also kinda wondering why that might be. I hopefully intend to use 70gn speer projectiles in it a lot,or either 64gn PowerPoint's or 65gn sierra gamekings. I just can't see why 1:8 would be so terribly bad to be honest. Cheers,Pete
I was looking at ADI's load data (keep in mind that I consider ADI load data to be no better than you'd get throwing darts at a powder graph) a while back wondering about heavier bullets in the .22-250.
I don't have a .22-250, or any interest in owning one, to be able to experiment with this myself.
According to ADI's data:
40gn - .223 3750fps - .22-250 4300fps +550fps
50gn - 3450fps - 3900fps + 450fps
60gn - 3150fps - 3550fps + 400fps
70gn - 3000fps - 3200fps + 200fps
80gn - 2850fps - ADI don't bother listing heavier bullets for .22-250
90gn - 2450fps -
As you can see, you are getting diminishing returns as bullet weight increases in the .22-250, to the point that there may be no advantage at all in using heavier bullets in a tighter twist. Going to an Ackley chamber and a longer barrel would be more useful I think.
.220 Swift numbers show a similar thing:
40gn 4100fps
50gn 3950fps
60gn 3550fps
70gn 3350fps
.223WSM:
40gn 4300fps
50gn 4000fps
60gn 3700fps
70gn 3500fps
80gn 3350fps
Doing research using other data may offer more relevant numbers though.
Cooper wrote:No experience with a 1 in 8 twist 22-250. But given the bullet weights mentioned a 1in 10 would fine. Not sure how long the 70gr Speer are? But a 1 in 12 would nearly work at 22-250 speeds.
I would tend to go with what the gun smith recommended. Buy maybe he just has a 1 in 10 barrel on the shelf?
bigpete wrote:Gday all,just keen to hear some experiences and feed back on using a 1:8 twist barrel on a 22-250. I'm planning to rebarrel my 22-250 soon with one,I'd like to run a bit heavier projectiles than what I am at the moment. Currently anything I try over 55gn shoots like utter ******,mind you,I'm also thinking the barrel is possibly on its way out anyway. It was my late best mates and I've no idea how many rounds he put through it before he passed away,all I know is its 20 years old,I've had it for about 5 years,and I've probably put close to a thousand through it myself. So if anyone has the same potential set up I'd like to hear about it. Also,the gunsmith I spoke to today didn't seem that keen on a 1:8 twist barrel,he reckoned 1:10,so I'm also kinda wondering why that might be. I hopefully intend to use 70gn speer projectiles in it a lot,or either 64gn PowerPoint's or 65gn sierra gamekings. I just can't see why 1:8 would be so terribly bad to be honest. Cheers,Pete
JohnV wrote:The problem is the 22-250 is capable of some high velocities and if you start driving that same load and bullet into faster and faster twist rates the pressure can mount up quickly . Small diameter bores and bigger case loads of powder into faster twist barrels can spike pressure quickly . That's why the gunsmith does not like an 8 twist . The best idea is to use the minimum twist rate the bullet length needs to stabilize over the ranges used and don't go so heavy that the longer bullet will reduce powder room anyway .
The 65 grain Sierra GK will need a 1 in 10 at 3000 to 3300 fps span . What the max SAFE velocity and pressure will actually be in a 1 in 10 has to be found carefully .
JohnV wrote:The problem is the 22-250 is capable of some high velocities and if you start driving that same load and bullet into faster and faster twist rates the pressure can mount up quickly . Small diameter bores and bigger case loads of powder into faster twist barrels can spike pressure quickly . That's why the gunsmith does not like an 8 twist . The best idea is to use the minimum twist rate the bullet length needs to stabilize over the ranges used and don't go so heavy that the longer bullet will reduce powder room anyway .
The 65 grain Sierra GK will need a 1 in 10 at 3000 to 3300 fps span . What the max SAFE velocity and pressure will actually be in a 1 in 10 has to be found carefully .
bigrich wrote:bigpete wrote:Gday all,just keen to hear some experiences and feed back on using a 1:8 twist barrel on a 22-250. I'm planning to rebarrel my 22-250 soon with one,I'd like to run a bit heavier projectiles than what I am at the moment. Currently anything I try over 55gn shoots like utter ******,mind you,I'm also thinking the barrel is possibly on its way out anyway. It was my late best mates and I've no idea how many rounds he put through it before he passed away,all I know is its 20 years old,I've had it for about 5 years,and I've probably put close to a thousand through it myself. So if anyone has the same potential set up I'd like to hear about it. Also,the gunsmith I spoke to today didn't seem that keen on a 1:8 twist barrel,he reckoned 1:10,so I'm also kinda wondering why that might be. I hopefully intend to use 70gn speer projectiles in it a lot,or either 64gn PowerPoint's or 65gn sierra gamekings. I just can't see why 1:8 would be so terribly bad to be honest. Cheers,Pete
well pete , this is just my layman's opinion , but i think at the velocities that a 22-250 can push a projectile , a 1-8 twist may be twisting the projectiles too fast . can't remember where i read it , but too much rotational speed in a bullet can make it self destruct . i'm sure if i'm wrong someone will correct me
i beleive the standard twist for a 22-250 is 1-14 . it stands to reason that a 1-10 would be spot on for the heavier projectiles you want to run .
i recently sorta-kinda went through a similar thing with my 243 (yes , i remember you don't like 'em pete ) , in that i'm only interested in using projectiles in the 87-95 gn range . 87 vmax for longer range pest work, or switching to 95gn nosler bt's for pigs if necessary . standard twist in 243 is 1-10 , which is reaching it's limits to stabilise around the 95-100 gn projectile . IBI barrels from the bigC only come in 1-8 . yup great , my gunsmith agreed that twist should work better with the heavier projectiles than the standard ,and it does . it's only had 26 rounds through the barrel and the term "tackdriver" applies
so i reckon go with what your smith recommends , and bigpete will be a happy man
bigpete wrote:Fwiw,I dont care about whether it's 200fps or 600fps over a 223. Thats not a concern for me at all. The main aim for me is to be able to run a heavier bullet in case I come across game other than foxes. Also,just because thats what I want lol. Interesting to note that nosler chart,a lot different to ADI data !
bigrich wrote:250 savage is a good caliber , so is 257 bob . actually , a wildcat in the same group i haven't heard much of is 308-25 . you could neck up 243 brass maybe
anyway ,what your aiming to do with your 22-250 is acheivable , but going faster twist to stabilise heavier projectiles may drop some accuracy with lighter projectiles . ballistics is a compromise at times
bigrich wrote:well pete , this is just my layman's opinion , but i think at the velocities that a 22-250 can push a projectile , a 1-8 twist may be twisting the projectiles too fast . can't remember where i read it , but too much rotational speed in a bullet can make it self destruct . i'm sure if i'm wrong someone will correct me
i beleive the standard twist for a 22-250 is 1-14 . it stands to reason that a 1-10 would be spot on for the heavier projectiles you want to run .
i recently sorta-kinda went through a similar thing with my 243 (yes , i remember you don't like 'em pete ) , in that i'm only interested in using projectiles in the 87-95 gn range . 87 vmax for longer range pest work, or switching to 95gn nosler bt's for pigs if necessary . standard twist in 243 is 1-10 , which is reaching it's limits to stabilise around the 95-100 gn projectile . IBI barrels from the bigC only come in 1-8 . yup great , my gunsmith agreed that twist should work better with the heavier projectiles than the standard ,and it does . it's only had 26 rounds through the barrel and the term "tackdriver" applies
so i reckon go with what your smith recommends , and bigpete will be a happy man
bigpete wrote:He has 1:8 on the shelf too. The speers are reasonably long,obviously not as long as a boat tail but long enough. I have been reading a bit more on the subject and it does appear that OVERstabilisation can possibly be an issue,which is equally a problem.
bladeracer wrote:bigrich wrote:well pete , this is just my layman's opinion , but i think at the velocities that a 22-250 can push a projectile , a 1-8 twist may be twisting the projectiles too fast . can't remember where i read it , but too much rotational speed in a bullet can make it self destruct . i'm sure if i'm wrong someone will correct me
i beleive the standard twist for a 22-250 is 1-14 . it stands to reason that a 1-10 would be spot on for the heavier projectiles you want to run .
i recently sorta-kinda went through a similar thing with my 243 (yes , i remember you don't like 'em pete ) , in that i'm only interested in using projectiles in the 87-95 gn range . 87 vmax for longer range pest work, or switching to 95gn nosler bt's for pigs if necessary . standard twist in 243 is 1-10 , which is reaching it's limits to stabilise around the 95-100 gn projectile . IBI barrels from the bigC only come in 1-8 . yup great , my gunsmith agreed that twist should work better with the heavier projectiles than the standard ,and it does . it's only had 26 rounds through the barrel and the term "tackdriver" applies
so i reckon go with what your smith recommends , and bigpete will be a happy man
I found that 52gn bullets swaged from .22LR brass (a very thin jacket) will start to come apart over 3000fps in my 8"-twist barrel, at 3300fps none of these bullets reached the target. This is the region from 270,000rpm to 297,000rpm. The guy that made them was shooting them in a 12"-twist .22-250 at much higher velocities with no problems, but to make 270,000rpm in a 12"-twist requires 4500fps. I've shot 35gn Hornady bullets at 3900fps in my .223 with no problems, making 351,000fps, but commercially made bullets have thicker jackets. I haven't heard too many anecdotes of commercial bullets vaporising at "normal" velocities. Larger diameter bullets will suffer more, but it's harder to push them to such velocities.
JohnV wrote:Jacketed bullets blowing up can be caused by a few things .
Thin weak jackets .
Fractured jackets ( popped jacket )
Very hard brittle jackets
Rough deep engraving rifling .( cut rifling worst )
Long barrels .
High velocity / spin rate making the above more likely .
There is a couple of others I can't recall .
Usually a combination of the above will do it .
Berger had a problem some years back with it's target bullets with a thin J4 jacket blowing up in cut rifled barrels , Krieger I think . It was just a bad match of deep not so smooth lands and thin jackets driven hard . Now Bergers target bullet has a thicker jacket .
Grandadbushy wrote:G'day bigrich, mate i've had a 1-8 in 22-250 shot excellent with hornady 69gr projectiles also had one in 22-250 AI, problem i had with both was if you tried to go too light in projectiles they'd blow out i tried up to 80 gr but had no success one could talk about, i then rebarrelled both a year apart to 1-12 this was a more stable twist could still shoot 69gr but 60gr was perfect i then rebarrelled the AI to 1-10 but it was no better than the 1-8 or 1-12 the problem i found with trying to go from heavy to light projectiles in the same rifle in 250 with 1-8 was pressure and light to heavy was drop in poi in a big way i reckon if i was to do it again i would prefer to tighten the twist in a 223 to shoot heavier projectiles and shoot lighter as well there is a lot less pressures to worry about and with lighter projectiles you can get them moving as well my last barrel on the 250 sako was 1-14 i could go from 55gr to 40gr without altering my scope, it preferred the 55gr but i've now rebarrelled it back to 1-14 but it likes 50gr best i've tried to get it to shoot the 55's but i was wasting my time 3/4'' was best but the 50's shoot 5 into a 5cent piece so i'll stick with them mate the 22-250 in my opinion was designed to travel at speed for best effect with average weight projectiles once you start loading them up with weight and twist they die and produce high chamber pressures as was said above by someone, also barrel life is considerably less i believe a 243's would handle what you want better than the 250, just my point and experiences mate hope some may help
bigrich wrote:Grandadbushy wrote:G'day bigrich, mate i've had a 1-8 in 22-250 shot excellent with hornady 69gr projectiles also had one in 22-250 AI, problem i had with both was if you tried to go too light in projectiles they'd blow out i tried up to 80 gr but had no success one could talk about, i then rebarrelled both a year apart to 1-12 this was a more stable twist could still shoot 69gr but 60gr was perfect i then rebarrelled the AI to 1-10 but it was no better than the 1-8 or 1-12 the problem i found with trying to go from heavy to light projectiles in the same rifle in 250 with 1-8 was pressure and light to heavy was drop in poi in a big way i reckon if i was to do it again i would prefer to tighten the twist in a 223 to shoot heavier projectiles and shoot lighter as well there is a lot less pressures to worry about and with lighter projectiles you can get them moving as well my last barrel on the 250 sako was 1-14 i could go from 55gr to 40gr without altering my scope, it preferred the 55gr but i've now rebarrelled it back to 1-14 but it likes 50gr best i've tried to get it to shoot the 55's but i was wasting my time 3/4'' was best but the 50's shoot 5 into a 5cent piece so i'll stick with them mate the 22-250 in my opinion was designed to travel at speed for best effect with average weight projectiles once you start loading them up with weight and twist they die and produce high chamber pressures as was said above by someone, also barrel life is considerably less i believe a 243's would handle what you want better than the 250, just my point and experiences mate hope some may help
Thanks for the input on this subject GDB . There’s been a lot of science discussed on this, to hear from someone who’s been there and done it will be of use to bigpete who’s been pondering the issue.
Learned a bit more from the posters on this topic, I got involved in the discussion just for the knowledge.
It interested me cause I had a similar project jumping from 1-10 to 1-8 in my 243 . I’ve had great results from that . Hopefully bigpete’s project will work well too
bigpete wrote:Geezus,I even briefly wondered maybe I should just go 243.....