22-250ai throat question

[L1986]

Ive got a savage action that I put a 7 twist 22-250ai barrel on with the plans of shooting the 75amax out of. The problem is that this barrel is preety short throated and with the amax seated to the lands the base is well into the case, even past the shoulder body junction. By the measurements the amax is around 1.125" long and seated to the lands i have .475" or the bullet seated in the case. (See photo) my question is what should i do here? I really want to shoot the amaxs for the cost and BC and with the little load developement ive done with IMR-4350 they show some potential. But 4350 is bulky and with the short throat powder capacity is diminished. Should I try a different powder that is not so bulky, or maybe ream the throat? I guess im not quite satisfied with the current situation and any advice would be great. BTW mag length is not an issue its a long action. Thanks

 

[Eddie Harren]

Have it throated.

 

[Preacher]

What he said !!!!

 

[L1986]

Thanks guys thats what i was thinking. Any ideas on how much i should have reamed?

 

[22XC Guy]

Per Dave Kiff when I ordered a new reamer, he recommended 0.072" freebore for that bullet..

Steve

 

[r bose]

You're dealing with the same situation as guys who want to shoot 90g vld bullets in a 223. You have to get it throated for THAT bullet. But, if you go back to lighter, smaller bullets (45-55g) you might not be able to touch the lands.

I'd try R-17. I shoot a 6xc but start with 22-250 cases to fireform and can tell you, you'll be able to get plenty enough of that powder in the case for speed. In a 22-250 case when fireforming, I can get 39g on R-17 and with a 105g 6mm bullet it still pushes it over 3000 FPS.

 

[Billch]

Have it throated.

Much cheaper that getting a complete reamer. No need for that if you're satisfied with the rest of the chambering. Just have it throated - or even do it your self. I'd call Dave Manson at http://www.mansonreamers.com/. You may as well use that extra AI case capacity and make that A-Max scream.

For a 1-7 twist a freebore in the .070's - .080's would be the cats a$$ especially if you decide that you want to move up to an 80gr. LR BT or VLD later on. Otherwise, why'd you get a 7 twist, right? Hopefully not to shoot fifty grainers. ???
It'll work out.

B

 

[gimp4ever]

Might Try H414.Works GOOD in my 250AI 80gr JLK's.

 

[MrMajestic]

PTG has throating reamers. Just throated a T/C Encore barrel, chambered in 30/06 for the 208 gr. A-Max, by hand and the bore scope says I did great!

 

[benchracer]

Having your rifle throated makes sense here, especially with the 7 twist and AI case.

Throated or not, given that you are using 4350 now, RL-17 deserves a look, IMO. In my standard 22-250, it has outperformed all of the other powders I have tried, with both heavy and light bullets. I am getting 3600+ with 69 SMK's and 3900+ with 53 VMAX's from a 26" barrel. Both bullets are grouping in the .3's and .4's with RL-17.

 

[L1986]

Thanks for all the help guys! Got it throated and have some RL-17 loaded up and am going to give em a try today. Started at 34g and went up to to 38g in .5 increments. I will let you guys know how she shoots! Again thanks for all the input.

 

[L1986]

Well got out to the range yesterday and had some promising results. A couple sub .5 moa groups with 35&35.5g and 38 seemed to be on the hot side. Only down side is im not getting the velosity i think i should be getting. Im not sure my chrony is giving accurate results. With the 34g charge i was getting right at 3000fps and 38g was around 3300fps but again was a little to hot for my liking. This is out of a 26'' barrel. What do you guys think? Does this sound a little slow? Should i be questioning my chronograph?

 

[22DASHER]

Yeah that sounds a little slow, try H414 or H4350 if you can. Should get you some more speed.

 

[xswanted]

Try R17!

Might help that situation out.

 

[L1986]

Try R17!

Might help that situation out.

These speeds were with RE17.

 

[benchracer]

Well got out to the range yesterday and had some promising results. A couple sub .5 moa groups with 35&35.5g and 38 seemed to be on the hot side. Only down side is im not getting the velosity i think i should be getting. Im not sure my chrony is giving accurate results. With the 34g charge i was getting right at 3000fps and 38g was around 3300fps but again was a little to hot for my liking. This is out of a 26'' barrel. What do you guys think? Does this sound a little slow? Should i be questioning my chronograph?

Those velocities seem slow, by a 200 fps or better, in a STANDARD 22-250 with a 26" barrel. Not sure if the problem is your chrono or not. What is the base-to-tip overall length that you are loading to? How far are you loading the AMAX's from the rifling? What is your fired case capacity?

 

[L1986]

Well got out to the range yesterday and had some promising results. A couple sub .5 moa groups with 35&35.5g and 38 seemed to be on the hot side. Only down side is im not getting the velosity i think i should be getting. Im not sure my chrony is giving accurate results. With the 34g charge i was getting right at 3000fps and 38g was around 3300fps but again was a little to hot for my liking. This is out of a 26'' barrel. What do you guys think? Does this sound a little slow? Should i be questioning my chronograph?

Those velocities seem slow, by a 200 fps or better, in a STANDARD 22-250 with a 26" barrel. Not sure if the problem is your chrono or not. What is the base-to-tip overall length that you are loading to? How far are you loading the AMAX's from the rifling? What is your fired case capacity?

Not sure of the overall length but CBTO is 2.240 to the rifling and these were loaded .005 off the rifling at CBTO 2.235. Not sure on case H2O capacity but i can put around 44 grains of RE17 in there.
I did a seating depth test today and fired 30 rounds all with 35 grains of re17 at different depths and all chronoed between 2991-3114 with the chrono 10ft from the muzzle. Im going to try this load at maybe 300 yrds next and check the drop to see if the numbers match up.

 

[benchracer]

[/quote]

Not sure of the overall length but CBTO is 2.240 to the rifling and these were loaded .005 off the rifling at CBTO 2.235. Not sure on case H2O capacity but i can put around 44 grains of RE17 in there.
I did a seating depth test today and fired 30 rounds all with 35 grains of re17 at different depths and all chronoed between 2991-3114 with the chrono 10ft from the muzzle. Im going to try this load at maybe 300 yrds next and check the drop to see if the numbers match up.
[/quote]

Knowing the base-to-tip OAL and the average water capacity of your fired cases would go a long way in helping to figure out what is going on.

What brand of brass are you using?

Also, what pressure signs did you see, if any, @ 38.0 grains?

 

[L1986]

Ok i measured five cases and got avaerage water capacity of 47g and loaded these are 2.690 OAL. This is lapua brass. Pressure signes i got was hard bolt lift and marking on the head.

 

[benchracer]

Ok i measured five cases and got avaerage water capacity of 47g and loaded these are 2.690 OAL. This is lapua brass. Pressure signes i got was hard bolt lift and marking on the head.

If you were getting marks on the case head with Lapua brass, I would consider that to be a definite sign of pressure.

I ran the numbers through Quickload and it is saying you should be hitting max around 3540 or so, with your high accuracy node showing up just below max @ 3500ish, using RL-17. The predicted powder charges are higher by about 3 grains, but that is consistent with QL predictions and RL-17 in the 22-250, IME. I have found the velocity predictions at max pressure to be pretty accurate.

At this point, I am inclined to question your chrono. I don't buy what it is telling you.