Faster Powders For Shorter Barrel .308 Win.

[Big7]

Looking for a powder that will produce as nearly as possible the FPS in a 16 or 18 inch barrel.
If such an animal exists.

I'm getting ready to convert one of my "regular" Mosin Nagants to a lightweight scout rifle.
I've already installed a synthetic aftermarket stock and fixing to start work on the barrel, trigger and scope mount.

7.62X54R has virtually the same case capacity as the .308 but the Sammy chamber specification is around 56,000 psi. So I'm looking to get a complete burn and decent FPS out of a shorter barrel so the powder is critical.

 

[furtaker]

Are you talking about using 308 data for 7.62x54? I've never been comfortable with substituting data for different cartridges even if they have similar case capacities.

 

[Big7]

Are you talking about using 308 data for 7.62x54? I've never been comfortable with substituting data for different cartridges even if they have similar case capacities.

NOOOOO.....

I never substitute data from even the most similar cartridges.

I'm wanting to know if anyone has used any particular powder to get more out of the 308 in a shorter barrel, maybe different from what they would use in sporter or target length barrel.

The problem with the Mosins Sammy rating is it it low because some production from different arsenals resulted in a few actions not being as strong as others. I have seen them tested to 80,000 psi with no issues but I wouldn't try it.

They get their power, comparable to the 30 06, from slow burning powder at lower peak pressure and a 29 inch barrel. In other words, a long, full burn.

 

[Big7]

I'm building something like these. I have that exact same stock but I'm going to machine my own base and it will be a little different than these. And... I prolly won't install a flash hider but if I do, it will be permanent and will count toward the barrel length depending how short I go. Another possibly is a threaded muzzle and a detachable can. Doubt it will have a bipod as the intent is to build a scout rifle.

 

[bullgator]

I would look at data written for service rifle loads such as the M1A. Something from Varget and faster. Reloader 15, IMR 4064, and N135-140 might be where to start.

 

[menhadenman]

Email the guys at Berger. Their techs get back to you asap on powder/bullet questions.

Or maybe search the web for guys that load for the Contenders. They make all kinds of rifle rounds in a pistol.

 

[rosewood]

Slower powder typically gives you more velocity even in short barrels to a point. However, you are going to get more flash and boom. To mitigate flash and boom, you need to go with a faster powder, but you may lose some velocity. Can't have you cake and eat it to.

I have proven with the chronograph that the .223 in a 14" contender barrel gets more velocity with H322 and a 45 grain bullet than it does with H335 and the same bullet. And there is significant less boom with H322. However, this doesn't always hold true. Some will argue the powder that gives max velocity in a long barrel will always do so in a short barrel, this may apply in most cases, but has been proven to not always apply.

H322 may be a good powder to try out. It is on the fast end of available data for .308 sized cases.

Maybe someone will chime in with their own testing in a .308 sized case in a 18" rifle barrel.

Dang, did I just contradict myself??

Rosewood

 

[Jester896]

most of the burn is going to be in the first 12" of barrel for most of those mid range powders...I don't know if it would matter that much as long as the velocity was where you wanted it.

Just a small observation in what I have done. The load as used in my 26" .308 works pretty darn good in my 20" but has the extra boom...still very close to the same accuracy @ 100 but that may be the difference in the rifle itself...it may not be as accurate as the other rifle. I'm sure I will play with it a little on seating depth and such at some point. As it is now it could only be out an inch at 300. That should hunt pretty good if that is the goal.

 

[bullgator]

Dang, did I just contradict myself??

Rosewood

I believe you did……

 

[Jester896]

I should also add that I haven't checked the velocity on the 20" yet either.

I have used 175GMM in a 20" .308 and was able to put 2 rounds within 1/4" in the center of a sporting clay at 500 yards...had to use the 3rd round to break the outer ring

I can't wait to see if it matters

 

[rmp]

I’d try IMR3031, Big Game, and CFE223. Likely in that order but I also have plenty of those on hand.
IMR3031 shows 100% burn with a 16” barrel according to QuickLoad.

 

[bighonkinjeep]

I've been shooting a 16" .308 a pretty good bit for some years now. When I first cut it down I had some of the same "velocity concerns" as you. Also I let a lot of online naysayers touting accuracy and power concerns with a 16" barrel into my head as long barreled varmint and target rigs seemed to be the flavor of the day during that time period.

The reality I've found was that the 16" barreled .308 was just as accurate and has plenty of power out to any distance I'm comfortable taking a shot.
I tried several powders and even started shooting quite a few reduced loads using lighter bullets that help keep velocity up and have plenty of oomph to cleanly drop any buck. I've tried H4895, RL15, Varget and Power pro MR2000. They're all pretty much medium burn rate powders. The H4895 is probably the fastest burning that I've tried and has become one of my favorite powders in many cartridges because of its versatility. It works great in the compact and has the widest range of charge weight of anything else I've tried. This allows plenty of room for load development.and experimentation. H4895 Can be used with Hogdons Max load X 60% formula for reduced loads as well as worked up to max which allows development on both sides of listed "starting loads". In .308 I really like a 125gr at around 2400fps. Really accurate in my rifle and kills deer cleanly with almost no recoil and a significant reduction in blast.

I know youre interested in keeping velocity up and I think that lighter bullets would be more effective and probably safer in that regard than experimenting and working up to near max charges of faster powder in an old com block surplus.
At any rate Im pretty sure H4895 and light bullets.is what you're looking for. Near max loads with 125gr bullets are hauling the mail.
Heres a link to some Hogdon data so you can look up 7.62X54R. https://www.hodgdonreloading.com/reloading-data-center

Though im sure the test barrel is longer than 16" , It shows a 125gr with a max load of 54gr of H4895 running 3236fps in 7.62x54R at 45,700 cup

If you search online for "Hodgdon 4895 Reduced Rifle Loads" they provide data for several calibers as well as the Max X 60% formula in a pdf for use with that powder that will allow you to explore the full range of loads available. I find the reduced recoil and muzzle blast of a slight reduction to be quite enjoyable and plenty for hunting and plinking.

 

[rosewood]

I have found shorter barrels are more accurate as they are more stiff. However, the shooter is more accurate with a longer barrel, easier to hold steady (inertia of longer barrel resist movement more than short, and if irons, you have longer site radius). Trick is finding happy medium between the guns accuracy and your ability to hold the gun steady.

Rosewood

 

[Bobby Bigtime]

Seven, I have recently had super luck with viht-140 in my 7.62x54 carbine and finn 91. A friend who is a 308 fanatic swears by it and it is now his go to.

 

[BriarPatch99]

Looking for a powder that will produce as nearly as possible the FPS in a 16 or 18 inch barrel.
If such an animal exists

What ever powder that gives the most velocity in a 22" barrel....will also give the most velocity in 16"/18" barrel...

 

[Jester896]

might have try some N140...just recently picked up 8# for my Dasher