340 weatherby advice

[Thebear_78]

A buddy of mine has a weatherby mk v weathermark bronze in 340 weatherby than I’m seriously considering snatching up. I’ve been thinking I needed a magnum medium bore with longer legs than my 21” barreled 338 win. I used to have a 338 rum that was an absolute hammer. I have a bunch of 338 bullets from 185-300gr. I have a 338 lapua but its weight makes it less than ideal for hunting.

The weatherby looks great, good weight and weather resistant. This particular one has a good load for the 265 LRAB that he took a moose with last year. The down side is that 26” barrel.

My question is would it be sacrilegious to lop that barrel to 22”. I’m planning on getting the rugged 360 Alaskan ti suppressor whenever they come available again. It’s under 7” long but only 5.6 oz. It seems it would make a good match for the weatherby without getting too heavy.

Will the 340 lose too much velocity in a 22” barrel?

 

[salmonchaser]

My 338 Jarrett was built with a 25 inch tube to keep it a little shorter to match my 29 inch inseam. I wanted it at 22 and the smith suggested getting a 338 WM mag Using Jarrett data and 250 partitions I'm about 25 to 50 fps slower at 25 inch instead of 26, depending on load specifics.
The case capacity between the Jarrett and the Bee are almost identical, slight edge to the Jarrett. I would guess you could lose 50 to 100 fps going to 22.
I bet Fotis has tested the theory.

 

[SJB358]

I’d chop it Bear. For your use with a suppressor you’ll likely still be getting speeds that a 25-26” 338 Win can obtain. I’d bet you’ll still be north of 2800 with 250’s and around 2700 or better with that big 265 ABLR. My only reservation would be shooting it without a suppressor as it would be pretty jumpy but with the can it should make for a wicked combo.

 

[JD338]

What if you cut it to 23"?

JD338

 

[SJB358]

What if you cut it to 23"?

JD338

Jeeze Jim, it’d be an inch longer than 22”…. Duh

All kidding aside, the 340 is less likely to be hurt by the short tube than say a 300. It wouldn’t bother me a bit. Still going to be a set up for slaying moose..

 

[RL338]

Well I went the other way , hung a 28” barrel on my 340 Wby. I don’t hunt suppressed so the extra length isn’t an issue.
22” is about as short as I would go , a 340 is packing a lot of powder to be burnt.

 

[JD338]

What Rick said. My thoughts are an extra inch (23" vs. 22") might help burn that long powder column.
Either way, the 340 Wby would be pretty effective on moose or anything else you want to hunt.

JD338

 

[Thebear_78]

I figured 22” was probably a bare minimum for any kind of effective burn. I will have to check and see if there is enough meat to that thin barrel to do 5/8x24 threading. Barrel diameter might be the deciding factor on length or even if I do it at all.

 

[Slimfinn]

Could you have someone run some QLs at different barrel lengths to get a feel for %burn, velocity and such? Knowing a suppressor will add some V you could choose a load and barrel length that gives you the minimum you want then the suppressor puts a cherry on top

 

[RL338]

I will have to check and see if there is enough meat to that thin barrel to do 5/8x24 threading.

If it’s a #2 contour you might be stuck with 1/2”.
Wby thread #3 barrels 5/8”.

 

[Thebear_78]

If it’s a #2 contour you might be stuck with 1/2”.
Wby thread #3 barrels 5/8”.

It’s 1/2x28 at 26” now. It’s my hope that with the taper that 4” shorter should get me enough material to thread 5/8x24