Sub sonic 338 Win mag?

[Raffica762]

Anyone done this? I have a fast twist bbl ..so the big 300gr should be no problem

 

[VDVSNIPER]

I have a few .338 win mags and was thinking of making my ruger m77 into a subsonic rifle. Would be interested in seeing if anyone also has done this?

 

[biffj]

Never tried the win mag. Its a pretty big case for subsonics. I just shoot a .338 BR for that. Its based on the 308-1.5" case and can be loaded with 300gr SMKs at 1050fps or cute little 180 gr bullets at up to 2450fps in an 18" barrel. I use Lapua 6BR Norma cases necked up to 338. With my suppressor its the quietest rifle round I've heard yet.....hollywood quiet. It needs a 1-8 twist to keep from damaging your suppressor as those 300gr bullets are long. If your win mag is 1-8 you might give it a shot with trail boss or something of that sort. I'd be leery of trying though due to the capacity of the case. Even with trailboss you're going to have a very short fill and lots of airspace. With the BR accuracy is excellent subsonic. I'm guessing not so good with the WM.
The 300 gr slugs subsonic are a hard hitter though and the idea is a good one if you can get it to work. I just finished a barrel for my Desert Tech MDR and its quite impressive. Since I'm using a case based on the 308 its easy to find rifles to build. Anything that uses the 308 will work.

Frank

 

[Gunfighter14e2]

I've done cast subs in a 10 twist 300wm for many years now. Have a 285gr mold on order for my 9 twist 338LM that should be here in about 2 weeks or so. Projo nose an tail design dictates twist required. The shorter the nose the less twist required. A 175 smk in a12 twist at sub speed will start tumbling at about 150yds yet a round nose flat base 150-200gr sierra pro hunter will get to 600 yds nose on at sub speed from the same 12 twist.

 

[biffj]

You are right, the round nose and flat base will make the projectile much shorter and therefore require less twist to maintain stability. A long sharp pointed nose pushes the CG back and requires a faster spin to make it stable.
It is possible to shoot subsonics out of just about any round out there. Many are not ideal for it but it can be done. I'd hate to waste the time and effort to run my 338 Lapua Mag with subs.....especially when I've got a round that is ideal for subs.

Frank

 

[Gunfighter14e2]

The advantage is, no matter what stick you may leave the house with, it will do everything if need be. I do subs in everything I own, just in case.

 

[cav has been]

I don't know which mould maker you use GF but Accurate moulds shows a 305 gr 340 dia. mould that should produce a sledge hammer. I recently ordered a 245 gr. in .35 from them. 358 win is the next sub project.

 

[Gunfighter14e2]

I don't know which mould maker you use GF but Accurate moulds shows a 305 gr 340 dia. mould that should produce a sledge hammer. I recently ordered a 245 gr. in .35 from them. 358 win is the next sub project.

The 285 is coming from Accurate, when I ordered I never seen the 305/340 ? Well strike that, I may have seen it but with pure WW they say the one I ordered will come out of the mold at 285grs before the gas check an lube.

 

[Raffica762]

Thank you for the info looks like this will spin in a 1-10 twist

http://noebulletmolds.com/NV/product_info.php?products_id=4772

 

[Raffica762]

315gr 338 NOE