Looking for 25-308 AI Dimensional Drawing

[Shu]

Hi there,
I'm new to the forum. I have a Savage M11 Left Hand in 250 Savage AI. And I'm looking to rechamber to 25-308 AI for just a little more downrange Oomph.
I will stick with .257 bullets, as I already have alot of good bullets, and none in 6mm or 6.5. My son has a 25-308 AI in a right hand Rem 700, so I have a the dies and lot of 308 and 260 Remington brass.
So far I've only found 25-243 AI reamers on line. I assume that would be the same as 25-308 AI, as the 243 and 308 parent cases have the same headspace dimensions.
Anyway, I wanted to confirm the dimensions of the 25-308 AI and the 25-243 AI so the new chamber will work with my existing Dies.

 

[Ray Gross]

It is more or less the same thing called by different names. At heart it is a wildcat and there will be a variety of minor differences from print to print based on how tightly or loosely fitted a particular customer wanted the chamber to fit the chosen donor brass.

 

[Infrequent Shooter]

be sure to consider improved version vs AI. 30 degree shoulder with tapered case, I think. More knowledgeable folks will chime in (I hope). some people called this cartridge 25 Souper.

 

[Robert Weidler]

Hi there,
I'm new to the forum. I have a Savage M11 Left Hand in 250 Savage AI. And I'm looking to rechamber to 25-308 AI for just a little more downrange Oomph.
I will stick with .257 bullets, as I already have alot of good bullets, and none in 6mm or 6.5. My son has a 25-308 AI in a right hand Rem 700, so I have a the dies and lot of 308 and 260 Remington brass.
So far I've only found 25-243 AI reamers on line. I assume that would be the same as 25-308 AI, as the 243 and 308 parent cases have the same headspace dimensions.
Anyway, I wanted to confirm the dimensions of the 25-308 AI and the 25-243 AI so the new chamber will work with my existing Dies.

This is a work-up I did using Quick Design for JGS to make me a reamer. It's a fantastic cartridge and I love it. Getting 3000 fps is a no brainer using Berger 135 grain LRHT bullets. Note: it is easier and quicker to use 243 brass necked up with a mandrel when making loads to fireform. I also did this on a 6XC base. Not quite as impressive.

 

[Infrequent Shooter]

View attachment 1507387
View attachment 1507387
This is a work-up I did using Quick Design for JGS to make me a reamer. It's a fantastic cartridge and I love it. Getting 3000 fps is a no brainer using Berger 135 grain LRHT bullets. Note: it is easier and quicker to use 243 brass necked up with a mandrel when making loads to fireform. I also did this on a 6XC base. Not quite as impressive.

great work.

 

[Shu]

Great. Thanks guys. So it looks like Manson has the reamer; it's just not in their online catalog.
Measuring a fireformed (in my son's rifle) and full-length resized case it looks like the dimensions each of you provided will produce a chamber I can use. I will just need to back off a turn or so on the resizing die to get a slight crush fit. Now I just need to figure how long I want the throat. I plan on shooting 110 gr Nosler Accubonds, 115 and 120 gr Nosler Ballistic Tips and Partitions and the Barnes 100 gr. TTSX and 101 LRX bullets. Since my rifle has 1:10 twist, I don't think I could go with the 130+ gr Bergers, etc.

With the current 250 savage AI chamber, my rifle loves the Barnes 80 gr. TTSX, going 3300+ fps with 39.0 gr. of Varget. But that bullet gets pretty low energy out at 400 yds. Which is a common shot out here and probably near the limit of my ability from a field-type rest. Having the extra velocity, and being able to seat the longer bullets not so deeply into the powder space would make the 25-08AI attractive to me. It would probably have too much throat for the little 80 gr. TTSX's though.

An additional consideration for rechambering my rifle is that the reamer my local gunsmith rented to create the 250 Savage AI chamber produced too short of a neck, so factory ammo cannot be fired. He ordered a second reamer, but it was the same. I didn't think at the time (15 yrs ago or so) to ask whose reamer he was using. It works ok for me, as I trim new brass to a crush fit against the mouth of the case when I fireform, minimizing stretching of the case. The necks end up extra short though as blowing out the shoulder pulls brass out of the neck. Like I said, I make it work, but it probably further lowers the value of the rifle for when I'm gone and my sons, none of whom are left handed, go to sell it.

Finally, my one gripe with the 250 Savage AI is producing relatively straight walled cases from highly tapered brass. This produces a sort of bulge at that critical location where the web intersects the case wall. I haven't had case head separation (yet), but it bothers me. I've made some cases from 308 Winchester and 6.5 Creedmore brass. This takes care of the bulge issue, but both of these use enough extra brass to reduce case capacity at least a full grain. Since I'm already dealing with deep seating depths for the 100 gr. copper bullets (required here in Calif.) I'm limiting my powder selection.

 

[Shu]

Well, after looking around some more on this site, and doing more internet research based on all the helpful comments I've received here, I've determined I know much less than I think I do, and I apologize if I've come across as an arrogant fool. One thing I learned is that chambering and neck/throat reaming can be separate operations with separate reamers. That explains why my 250 AI chamber's neck is too short. It also tells me I need a gunsmith that knows what he's doing. I would prefer one I could drive to. Anybody have recommendations for good gunsmiths capable of doing a custom wildcat rechambering here in Southern California?