Reloading for a match chamber in .308

[Control for Smilers]

Hey guys. I recently acquired a very nice m40a1 clone from an OTD member. the chamber is VERY tight. the lead to the lands is VERY short. the rifle is VERY accurate. My issues are coming in reloading. i have to seat my projos a little deeper than listed min to keep them off the lands. I also use a lot of military brass...for the first few loads I have worked up..some of MY max loads for this rifle are at or a hair below published MIN loads in commercial brass. this doesnt bother me too much as I will probably save a few cents on powder over the time with this rifle. Here are my questions:

1. IF I am developing the same pressures with less powder due to the military brass and very tight chamber...Will I see comparable velocities? (I know i need to invest in a chronograph)

2. will my lead/throat eventually erode to where i can seat bullets longer?

3. would it behoove me to have the chamber reamed slightly larger or the lead cut slightly longer? Will this foul the rifle's accuracy? this rifle is 1/4 MOA all day w/damn near every projo I have used out to 400yards. 1 hole grps at 100yards...and my brother shot a 5 shot grp at 400yards that measured under an inch.

4. Any advise from people that know a lot more than me about loading for a match .308 chamber.

thanks!!

 

[BHJ]

If it's shooting that well it aint broke.
If it aint broke, dont fix it.

Forget all that "book" crap and numbers crap it doesn't make a hill of beans.
Gotta write your own book from here.
The more you actually shoot it the better you'll understand the rifles true dope.
Make a few notes and you're good to go.
You've got the tool and it sounds as if it's a good one, now work on the shooter

 

[Twitch2120]

The throat will erode over time but not as much as you will think. What did he have it throated for? 110 vmax? Which BTW is epic on sqirrels.

 

[1clearshot]

Sub'ed, have a Tikka T3 CTR on it's way and would like to learn the art of reloading.

the chamber is VERY tight. the lead to the lands is VERY short. the rifle is VERY accurate.

A friend has a 6.5 CM (or 6.5x47) that requires the case be trimmed shorter to actually fit into the chamber. Does shorter lead/ throat add to accuracy?

 

[Control for Smilers]

Im not sure. But the more i read on it...and my experience so far with the rifle...i think it is chambered in .308 fullbore. So I may need to get a set of small base dies to hit my 1x fired LC nato with. And i need a chrono. Going shooting tomorrow morning....Ill shoot out to 300 or 400yards without adjusting scope from 100yard zero and observe drop...maybe fig out a close velocity with a ballistics prog.

 

[Control for Smilers]

As to a shorter lead and accuracy, i think the chamber is meant to shoot 155palma. So the short lead is to get the 155 scenar pills right off or on the lands at 2.775....i think, lol

 

[jsmith15]

I have .308 virgin match brass for sale.

 

[Control for Smilers]

What do you need per case?

 

[Twitch2120]

Sub'ed, have a Tikka T3 CTR on it's way and would like to learn the art of reloading.



A friend has a 6.5 CM (or 6.5x47) that requires the case be trimmed shorter to actually fit into the chamber. Does shorter lead/ throat add to accuracy?

You can have a chamber and throat cut to any spec and that spec can be tailored to any brass or bullet combo. Shorter throat will make it easier to shoot lighter bullets well but it will cripple you trying to shoot heavier pills. The gun may shoot both accurately but you will be forced to seat the heavier, longer bullet deeper in the case. Thus you reduce powder capacity and increase pressure meaning you may not get the velocity required to make the heavier bullet worth it.

Good smiths will ask what bullet/brass combo you wish to shoot and cut your blank accordingly. This isn't to say another combo won't work but some people have a very specific shooting discipline in mind and having a very specific chamber will help meet their shooting goals.

To the OP, what is the twist rate and bbl length? That will indicate if it was set for palma or some other shenanigans.

 

[Control for Smilers]

isnt palma length. 24" shilen select match barrel 1/12 twist.