Short barrel Magnums

[2bfarming]

Could we gather all the short(22"or shorter) barreled magnum (300wm, 338L) discussion into one thread? I've read a lot of posts in unrelated or semi related threads that discuss it a bit but I'd really like to see some focused discussion on them.

All of you with experience please chime in and give us the run down especially on your exterior ballistics observations, loads, chamber dimensions, etc. Also for those of you who cut down a longer barrel what was your net loss in performance?

Its my understanding that there is a manufacture putting out a 20" but the name escapes me.

Pics are always appreciated.

 

[2bfarming]

Re: Short barrel Magnums

Found an old swat article that said Tac ops tested a 300wm. They cut a 26 down to 22 in one inch increments with no loss in velocity using 190's. They did go below 22 but did not mention the results.

I'd like to know how it would do with the 210's or 220's

I suppose barrel manufacture and chamber dimesion are going to be key factors to compare apples to apples.

 

[pappy83]

Re: Short barrel Magnums

I have a Savage that is 300WM with a 20 inch barrel. It was ordered from Effy at Savage to have same specs as a Precision Carbine only 300wm. It can push a 208amax at 2800ish with 76.7grains of H1000 in a winny case, and winchester mag primer. It is completely stock and averages around .600 inch groups at 200yds with this load. It is not very pleasant to shoot and is a good candidate for a brake. It also shoots 190smk very well. I almost sold it to buy a scope for a new project but deal fell through, I am glad it did, it shoots better then my more expensive 300wm with 26 inch barrel right now.

I have a 20inch LTR in 300 saum that will pretty much match the Savage velocity wise with re17 powder. It shoots some loads as well as the savage but does not shoot as many loads as well. It is in a manners stock with mini chassis.

Velocity wise the magnums loose more per inch then the .308's do. I have a 14.5 inch Savage that is 2600fps with 46.2gr of varget in a Hornady case and 200 primer. It did not lose much velocity at all going from 20 inch to 14.5. It is very accurate, and very predictable not much change from cold bore, clean bore, or warm barrel. here is the 300wm with the 308

 

[jrob300]

Re: Short barrel Magnums

Tikka 300WM with 22" barrel:

Chamber has a longish throat as 208 Amax's are out to 3.650 .010 off the lands. It generates 2870 fps in Fed./Nosler brass... a little more in Winchester. It's a hammer to over 2000 yards.

John

 

[2bfarming]

Re: Short barrel Magnums

Thats the kind of stuff I was hoping to see and hear. jrob is that a factory tube you throated or custom?

 

[jrob300]

Re: Short barrel Magnums

That is a McGowen Precision #5 contour. The #5 is supposed to be .700 @ 27". So I figured at 22" it would be .725 or so, but they took the .700 dimension back to 22", so it has a pretty steep taper.

John

 

[louboyd]

Re: Short barrel Magnums

The main characteristic of short magnums is lots of muzzle blast.
That requries hearing protection but once you have that you might as well add an efficient brake. Then you can either make the whole rifle lighter or use an larger cartridge and still be able to tolerate the recoil.

I shoot a Pauza P50 carbine which is a semi-auto 24" barrel 50 BMG. It has a fairly efficient brake. Though the muzzle blast is brutal the recoil is not. I can shoot it standing offhand with no difficultly though not rapid fire. It delivers about 2400 ft lbs of energy at 1200 yards supersonic with mil-surplus ammo. This is the gun's designer Robert Pauza shooting the long barrel version.
http://www.freshourmfg.com/gunbuild/p50/pauza.mpg

The ultimate short barrel magnum is the Carl Gustav recoilless rifle.
http://www.youtube.com/watch?v=VvRzOO_avCc

 

[grouse]

Re: Short barrel Magnums

What about a 300wsm? Anyone have any ideas on how the muzzle blast would be on one of the Short action magnums?

 

[Gray]

Re: Short barrel Magnums

The WSM's will be about the same as far as muzzle blast, 22" Barrel is the shortest you want to go with any magnum. Too much powder to burn in a short tube. Surgeon Rifles has a 22" 300 Win. Mag up for grabs on their site now.

 

[2bfarming]

Re: Short barrel Magnums

Special, I would agree that optimal performance will only be achieved in the longer barrels but other than some extra flash and a little loss in the MV dept. whats the down side?

IF I can spit a 210 at 2750-2850 am I not FAR exceeding what any non magnum could do in the same short platform? Jrob is knockin on 2900's door. Would he lose 100-150fps by cutting it 2 more inches? Maybe but I'd guess somewhat less. Even at 2700 I'm gonna put the hurt on stuff well past 1200yds. Plus the fact that I'm shooting from 4300-5500ASL most of the time.

Experts, please chime in on the possible neg effects of unburned powder in short barrels. Excessive fouling, probs with can's etc?

Has the question been answered unequivocally that you will have unburned powder coming out the muzzle of 300wm with a 20" bbl? I'm sure this is dependent on the type and amount used but generally speaking. I think its at least a possibility that the majority has been used up but I'm just guessing.

Is'nt it true that even though the powder has completely burned, as long as the bullet is still in the pipe the pressure created by the powder is still accelerating the bullet?

I see barret has a 20" 98b in 338LM no less.

 

[2bfarming]

Re: Short barrel Magnums

I forgot pappy is running about 2800 out of a factory 20" Thats VERY exciting to me.

 

[wmr264]

Re: Short barrel Magnums

I hope this thread takes off I have A ton of ?'s about this but very few answers.
standard vs tight bore/standard vs 5r ?

Some good stuff already keep it coming.

 

[Mackay Sagebrush]

Re: Short barrel Magnums

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jrob300</div><div class="ubbcode-body">Tikka 300WM with 22" barrel:

Chamber has a longish throat as 208 Amax's are out to 3.650 .010 off the lands. It generates 2870 fps in Fed./Nosler brass... a little more in Winchester. It's a hammer to over 2000 yards.

John </div></div>

A truly fine looking Tikka there!

 

[2bfarming]

Re: Short barrel Magnums

wmr264, ask the questions.

 

[wmr264]

Re: Short barrel Magnums

even if you were not burning all the powder couldnt you back off the load a little and still way out preform the 308's with a 210 or 208 ?