22-250 freebore

[4xforfun]

A friend of mine is getting his 22-250 re-tubed to another 22-250. He wants to shoot the Berger 80 VLD and has the 1-8 twist Krieger. My smith has a reamer with a .025 freebore, but also has a throating reamer. I was going to send him a dummy round seated the way we want,(way long) but the smith says he wants a "hard number"....ie.. .090, .110.....etc. What did you guys use for freebore when using the heavy's. I was thinking .100 freebore.

What say you,

Thanks,
Tod

 

[areaone]

.075 fb n a 22 250 ai works fine on 75 gr a max.

 

[benchracer]

A standard 22-250 reamer naturally has a LOT of freebore. With a 69 SMK (I didn't measure any heavier bullets because I don't have a tight enough twist to use them), my base-to-tip COAL to the rifling is 2.507". My previous barrel yielded COALs within .005 of my current one.

I would expect the 75 AMAX, being around .200 longer than the 69 SMK (with a much longer ogive), to easily allow room for seating the boat tail even with the bottom of the case neck using a standard reamer. IMO, trying to manipulate freebore in 22-250 is going to leave you chasing your tail. The standard freebore in 22-250 is already suitable for heavy bullets. If only the standard twist rate were spec'd to match...

 

[JASmith]

I just went throught the excercise of calculating the "correct length" for the freebore of a 20 Caliber. Won't iknow if the calcs are reasonable unti the reamer is cut the barrel chambered, etc.

First question you should ask is "How close is his existing freebore to being long enough for the desired bullet?"

Second question: "What is the existing freebore length?" (Gunsmith shoul be able to determine this.)

After that, it is a matter of addition and subtraction subject to throat wear.

Since the gunsmith wants length specified in 10 mil increments, round down to give a margin for wear.

 

[4xforfun]

A standard 22-250 reamer naturally has a LOT of freebore. With a 69 SMK (I didn't measure any heavier bullets because I don't have a tight enough twist to use them), my base-to-tip COAL to the rifling is 2.507". My previous barrel yielded COALs within .005 of my current one.

I would expect the 75 AMAX, being around .200 longer than the 69 SMK (with a much longer ogive), to easily allow room for seating the boat tail even with the bottom of the case neck using a standard reamer. IMO, trying to manipulate freebore in 22-250 is going to leave you chasing your tail. The standard freebore in 22-250 is already suitable for heavy bullets. If only the standard twist rate were spec'd to match...

Like I said....he has a .025 freebore reamer. I have no idea if that is a "standard reamer". Just looking for a "hard number".

Thanks areaone for your imput.

 

[STS]

I have a reamer with .045 freeborn. That's a good number that will cover most of the common bullets in the 50 to 60 grain range. If you stay with the lighter bullets .020 works well.

 

[40X Guy]

.075 freebore is perfect for 75 A-Max as mentioned. And your .100 freebore figure will be on the money for most bullets in the 80 grain class.

Frank

 

[4xforfun]

.075 freebore is perfect for 75 A-Max as mentioned. And your .100 freebore figure will be on the money for most bullets in the 80 grain class.

Frank

Great!!!

Thanks, that is the info I needed!!

Tod