I have a 26" 8" twist Brux bbl #4 contour. Rifle was suppose to be my predator rifle. But took it on Prairie Dog shoots a couple of years ,after I bet a 1,000 rounds of all hot loads the bullets were key holing at 25 yds. Gunsmith did a chamber cast and I guess bore scoped it. He said throat is fried but didn't notice any fire cracking past the chamber. He said he could cut off up to an inch and re-cut the chamber for $250. Cost of new bbl is $350 and to chamber and fit to action is another $350.Any experience with this scenario,what to do ?
Throat of 22/250 is fried
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OK...... first things first. KEYHOLING??? Keyholing means that the bullets are going unstable, tumbling through the air like a thrown stick.
I've got barrel with the first 2-3 inches of the riflings GONE. And they don't keyhole. I think maybe your bullets are leaking...bleeding out...coming apart.... do you notice any black swirls on the 25yd targets?
If the throat has become rough it can cause bullets to fail BUT.......
Secondly....Your gunsmith says "throat is fried but no firecracking past the chamber"
This is obviously some sort of mis-communication but confusing nonetheless.
I will suggest that IF you've an inch or so of firecracking/roughness in the first inch of the lands and if he's willing to cut off and re-do for 250.00 then having it done is an option that may give you another 500rds.
But I further suggest that your bullets ARE NOT keyholing......... and that you do some more testing to see if they're coming apart.
Humor me please..... maybe post a pic of the 25yd target even???
I've got barrel with the first 2-3 inches of the riflings GONE. And they don't keyhole. I think maybe your bullets are leaking...bleeding out...coming apart.... do you notice any black swirls on the 25yd targets?
If the throat has become rough it can cause bullets to fail BUT.......
Secondly....Your gunsmith says "throat is fried but no firecracking past the chamber"
This is obviously some sort of mis-communication but confusing nonetheless.
I will suggest that IF you've an inch or so of firecracking/roughness in the first inch of the lands and if he's willing to cut off and re-do for 250.00 then having it done is an option that may give you another 500rds.
But I further suggest that your bullets ARE NOT keyholing......... and that you do some more testing to see if they're coming apart.
Humor me please..... maybe post a pic of the 25yd target even???
MilGunsmith
Member
What weight bullets? A 1-8" twist will really spin a light bullet apart. That was the problem with the .220 Swift when it came out.
75gr +
I mostly shot the heavies . Lots of 77gr Sierra TMK and 75gr Amax .I was even able to consistently soda pop cans at 350 yds with 90gr Sierra MK . But have shot a lot of 55gr bullets and they were accurate enough to turn varmints inside out. But last time in varmint field I was missing badly on easy shots.( Worried my new Zeiss V6 was bad) Then shot on paper and several bullets key holed at 25 yds. Going to Montana in a couple of weeks,22/250 is staying home.
I mostly shot the heavies . Lots of 77gr Sierra TMK and 75gr Amax .I was even able to consistently soda pop cans at 350 yds with 90gr Sierra MK . But have shot a lot of 55gr bullets and they were accurate enough to turn varmints inside out. But last time in varmint field I was missing badly on easy shots.( Worried my new Zeiss V6 was bad) Then shot on paper and several bullets key holed at 25 yds. Going to Montana in a couple of weeks,22/250 is staying home.
MilGunsmith
Member
Did you change bullet makes or construction? I have a 22/250AI with a 1-8" barrel and use the 75gr Barnes X bullets. I tried some thin jacket 55gr varmit bullets and they came apart. At work we tried a 1-7" 22/250AI with 77gr SMK, they came apart at 4000fps. Then tried a 1-9" with the same load and they shot well. Try slowing the bullets down and see what happens.
The bullet that went sideways thru the target ,was a bullet that I shot 100s of times.
You say "the bullet" as if you've only one instance......
Bear with me here, it's basically physically impossible for your bullets to be truly keyholing. I'm not arguing with you, I'm asking, I am curious, VERY curious. Are there multiple sideways imprints? If you shoot 5 rds do they just splatter and leave random bullet shaped tears in the paper?
Bear with me here, it's basically physically impossible for your bullets to be truly keyholing. I'm not arguing with you, I'm asking, I am curious, VERY curious. Are there multiple sideways imprints? If you shoot 5 rds do they just splatter and leave random bullet shaped tears in the paper?
Some were Oblong oval shape
Like I posted earlier it was a great shooter in the field until that last time missing badly on easy shots. Put rifle away and grabbed my 204 ,(Squirrels everywhere didn't have time to mess with it) So shot on paper at 50 yds with 60gr bullet and 77gr TMKs . A couple of the 77s made a perfect profile hole,others the hole looked a V shape 60gr bullets were holes but large groups. This rifle was supposed to be my predator rifle(#4 contour barrel),but coyotes are heavily pressured and elusive. So shot a lot of varmints instead. So thinking maybe I'll get a heavier barrel like a #5 or 6 and a slower twist and shoot slower. Still like everyone else have plenty of rifles to take to MT next week for prairie dogs.
Like I posted earlier it was a great shooter in the field until that last time missing badly on easy shots. Put rifle away and grabbed my 204 ,(Squirrels everywhere didn't have time to mess with it) So shot on paper at 50 yds with 60gr bullet and 77gr TMKs . A couple of the 77s made a perfect profile hole,others the hole looked a V shape 60gr bullets were holes but large groups. This rifle was supposed to be my predator rifle(#4 contour barrel),but coyotes are heavily pressured and elusive. So shot a lot of varmints instead. So thinking maybe I'll get a heavier barrel like a #5 or 6 and a slower twist and shoot slower. Still like everyone else have plenty of rifles to take to MT next week for prairie dogs.
It usually takes more than just some throat wear to get to keyholing.
Keyholing only occurs when there is NO spin on the bullet.
Under-size bullets in low pressure guns since the force put on a bullet in a higher pressure gun sill often obturate anyway unless the bullet is well under diameter.
Complexity gone rifling (as in corroded out or scraped out with a steel rod) will also lead to tumbling.
It usually takes almost all the barrel being badly damaged though.
Spinning a lightly constructed bullet to fast often results in some 'interesting' holes in a target but rarely full keyholing.
Even if it comes apart the largest pieces are usually still rotating.
Keyholing only occurs when there is NO spin on the bullet.
Under-size bullets in low pressure guns since the force put on a bullet in a higher pressure gun sill often obturate anyway unless the bullet is well under diameter.
Complexity gone rifling (as in corroded out or scraped out with a steel rod) will also lead to tumbling.
It usually takes almost all the barrel being badly damaged though.
Spinning a lightly constructed bullet to fast often results in some 'interesting' holes in a target but rarely full keyholing.
Even if it comes apart the largest pieces are usually still rotating.
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It's kind of funny how you can take a perfectly good 22 barrel, run a 22-250 reamer in it and voila the throat goes to hell in 300 rounds or so or about the time load development is shook out. Have a 22-250 AI in the shop now with 250 rounds through it and the throat is gone for about an inch or so. I call it the why or why round! We need a barrel company to start making Kryptonite barrels to chamber up.
MilGunsmith
Member
We had a M240 barrel here that we shot over 50,000 rounds thru it. The rifling was gone all the way up to around 4" from the muzzle. It still shot a 12" group at 200 yards.
I would have scrapped that barrel out long before.
MilGunsmith
Member
This was part of an endurace test on the machine gun and new barrel materiel.
I am doubtful that a bad throat with little to no fire-cracking is the issue. Try a different bullet, say a 55 gr Nosler BT, maybe you got a bad box of bullets. I have a 243 sporter that literally has no rifling left in the first 3 inches forward of the chamber but it will still shoot 3 shot groups into an inch @ 100 yds. Give a different bullet a try before spending money on something that may not be the issue.
Edited to add - I have burned and fire-cracked the throats badly on quite a few rifles through the years, mostly 223 and 22/250, and never experienced keyholing with any of them.
I recommended the Nosler BT because they have a slightly thicker jacket and are generally quite accurate so they would make a good test bullet to see if it is a bullet issue or a barrel issue.
drover
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redrockranger
Member
New barrel
Time for a new barrel. Try a 22 BR chambering. 0 free bore,12 twist. Not quite a 22-250 but close. Burns less powder. Fine accuracy.
Time for a new barrel. Try a 22 BR chambering. 0 free bore,12 twist. Not quite a 22-250 but close. Burns less powder. Fine accuracy.
How is it "not quite a 22-250 but close?"
velocity?
With light bullets (12t) I shoot my 22BR's faster than 1 22-250 can run.....
Muller Works bbl
Right now I can get a #5 contour 12" twist Muller works bbl. Previous bbl was a #4 contour.(Predator rifle,sporter stock) I'd really like a #6 contour,but might have to wait a few months .Is the difference worth the waite ? More varmints than predators around.I want to shoot 53gr V-max up to 64gr Berger bullets)
Right now I can get a #5 contour 12" twist Muller works bbl. Previous bbl was a #4 contour.(Predator rifle,sporter stock) I'd really like a #6 contour,but might have to wait a few months .Is the difference worth the waite ? More varmints than predators around.I want to shoot 53gr V-max up to 64gr Berger bullets)
redrockranger
Member
22 br
My 40X 22-250 would shoot 55gr soft points @ 3750 fps @ the muzzle. 22 BR does about 3500 fps with 53 V Max. 22-250 lasted 3000 and and was lucky to hit a 50 cent piece @ 100 yds. I believe the 22 BR is little more accurate, Never shot any thing smaller than 50 gr in a 22 centerfire.
My 40X 22-250 would shoot 55gr soft points @ 3750 fps @ the muzzle. 22 BR does about 3500 fps with 53 V Max. 22-250 lasted 3000 and and was lucky to hit a 50 cent piece @ 100 yds. I believe the 22 BR is little more accurate, Never shot any thing smaller than 50 gr in a 22 centerfire.