.243 wssm Barrel length

[mrbeav]

I just finished building a 243 wssm with a Pac-nor barrel and a Savage action. The barrel has 31.864" of rifling in front of the chamber. The muzzle has an 11 degree crown. The chamber was cut with a minimum dimension reamer rented from Elk Ridge and I stopped cutting when it barely closed on the go-gage. It is a 1 in 10 twist. It shoots 88 Berger's, 87 v-max, 90 Berger's, 80 Berger's, and 85 sie hp game kings all between .5" and .75" at 100yds. Looking for suggestions. Is my barrel to long? I loaded all these bullets with IMR4350, and H4831sc. all suggestions will be appreciated. thanks Mike B.

 

[TRECustom]

It is very hard to part off perfectly good barrel, but I'd guess that it is longer than it should be. I measure barrel length the same way that BATF does. Close the bolt, ease a cleaning rod down through the bore to touch the bolt face. Mark the rod at the muzzle, pull it out and measure that length. By that measure, I would guess that somewhere around 27" is probably optimum for all-around use. I'm guessing that the barrel is either a bull or a fairly heavy straight taper and the rifle is bedded and floated in a good stock. Not Tupperware.


IMR 4350 should be a good powder for 80-90gr bullets. If you're pushing it hard, try backing it off 1 or 2 grains and see if it tightens or loosens the groups. If you're not showing pressure, bump the loads up in 1/2 gr steps, but watch the 4350 closely. It will sometimes show extreme pressure all of a sudden, even at 1/2 gr bumps. Try some different primers, too. I've started using CCI 250 BR-2 primers recently and they seem to have a very slight edge over 210-M's.

If your lathe spindle isn't too long, you can easily part off and crown in 1/2" or 1" increments without removing the receiver, until you hit a sweet spot, but I would start to cut in 1/8",or less) increments at about 27", and would not go below 25".

If you're using a chronograph, pick a load with a low standard deviation and use it while you tune the barrel. Also, while you are looking for the right combination, you can load 3 rds to try instead of 5. 3 won't prove that it's a good load, but if the 1st 2 rds are tight, shoot the 3rd one. If it stays in, note it and go back with 5 rds. But if the 2nd or 3rd rd goes out, move on. That load is not going to shoot 5 good ones in that barrel length.

You should be able to shoot sub 1/2 moa with the right combo.

Now for the disclaimer: these are my opinions, and work for me most of the time. If something else is wrong, untrue action, bedding problems, inconsistent handloads,etc.,,all have happened to me) this process won't cure the real problem.

Didn't intend to write a novel. Good luck, Tom

 

[mrbeav]

Thanks Tom,
I have a Smithy Granite 1340I lathe, mill, drill combo and working thru the tail stock with a steady rest is no problem. Just takes allot of time indicating it in. All my guns I built I indicated them to the bore. I seen some gunsmiths just chuck up the barrel and start cutting. This rifle is in a Sharpshooter Supply laminated thumbhole br stock and it is pillar and glass bedded. the barrel is 1.3" at the action and .980 at the muzzle. thanks again Mike

 

[TRECustom]

Let us know what you decide, and how it comes out.

I'm betting you'll get it to shoot like you want it to.

Tom