building WSM short -action carbine
Greetings to all!! I need help establishing guidelines for building a .270 wsm carbine.I'd like to go with a 16.5" barrel if it is practicle.Will this generate too much muzzle blast? Can it be loaded with powders that will burn thoroughly in such a short barrel? What is the best twist rate for a 130 grain bullet? Lastly what are your opinions on the best short actions? Thanks in advance for your [:D]recommendations.[:D]
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I would have to look at my charts to give you an accurate twist rate. But the barrel length will only affect velocity. It has been proven that all modern powders, are burned within the first few inches of the barrel, contrary to old logic. Even big over-bores like the 30-378 wthby burn all of their powder within the first 5 inches of barrel. The blast at the muzzle is the hot gasses expanding and "burning" due to an increased reaction when these superheated gasses are exposed to oxegen, (a fuel for the fire). It is not powder burning, it's the gasses hitting the air.
That being said, I guess it would work just fine. However, much velocity will be lost with that short of a tube, and recoil will be dealt with on the back end. I would think that short of a barrel would negate the whole purpose of that particular chambering, but that's just my logic.
I'm a man,....but I can change,.....If I have to,......I guess.0 -
From what I understand, getting these short fat cartridges to feed properly from a standard action can be a real hassle. It requires quite a bit of magazine feed rail modification, and must be done right or they are a lot of trouble. You might be better off to buy a factory gun and shorten the barrel. You will probably lose around 50-75 fps per inch as you shorten it. Then you might as well have a standard 270. 0 -
I have just had a 338 WSM built. I am working on the stock now. These short fat cases are a problem to feed right, but it can be done. I built my 338 WSM out of a 1909 Argentine action and it works perfict. My rifle will only hold 3 rounds in the magazine. Also all of the short magnum cases are the same size. If you size a sm case up or down you will change the angle of the shoulder. Care must be taken to avoid this or the round will not fit in the rifle. I formed my 338 WSM brass from 300 WSM brass. I exsperanced this problem first hand. There are 2 ways to avoid this shoulder problem. Re adjust the sizer die so the shoulder angle won change or buy a neck sizer die for your calaiber. I bought a 338 WSM neck sizer die for $40.00 to solve this problem.
Good hunting
Hornet0 -
Hornet, did you do the rail mods yourself or have a gunsmith do it? Would like to correspond with you on this subject. Please contact me at jmothes@pld.com Thanks, James. 0 -
thanks for the info,gentlemen.From what I'm reading i'm thinking that a push feedaction instead of a controlled feed might be the answer to the feed controversy.Thanks again.[:)] 0 -
I finished a project rifle based on the WSM. case about four months ago. My Son bought a Browning .300WSM and was slightly disenchanted with the amount of bullet that was going down into the case. He wanted to use a 180gr. Scirroco(did I spell it right?)for moose next year. To make a long story short, we got into it when I took Winchester/Browning names in vain for not following Ackley and Wades advice of forty years past.....long neck-sharp shoulder and long throat it in a long action. I bet you guys are going to be all over me for repeating a sacriligious idea like this.
Anyhow, Rick Jamison has been doing similar stuff, sans the long neck, for years on the .404 Jeffery case. Coincidentally, I know him and his nephew(a killer gunsmith) fairly well so, after having a reamer and forming dies made and obtaining a .30 cal Lilja barrel, Brad Elder(Rick's nephew) built the gun for me on a Ruger MKII .300 Win. Mag. action. There was no action work neccessary. It feeds flawlessly.
For informations sake, my cartridge has a 40 degree shoulder(that I hate myself for-it should have been 35 deg. for ease of forming) and a .380 in. length neck. It was long throated to touch the rifling with a 150gr. Scirroco(long action) with the bullet base at the base of the neck. It holds exactly one grain more water than the .300WSM seated in this manner. It can still touch the rifling with a 130gr "X" bullet and have a full caliber of neck grip. Try that with a .300 WSM.
I'm going to make a .300WSM on a long action Savage and see what it will do with the bullet of my choice touching the lands. My son's Browning has a horrendous "freebore". The factory bullets are way below the neck base so they can fit in the short magazine. This does bad things to capacity. "A terrible idea for a sales gimmick, a magnum with a short neck on a short action"(Ackley's words, not mine).
Bud0 -
Warmgun;
A 16.5 inch barrel is a bit short and will produce impressive muzzle blast. This can reduced by trying different powders, to match burn rate and load to barrel lenght. A twist rate of one turn in 10 inches would work well with the .270 wsm. Call me prejudice, but I build on mauser actions exclusively. -You can obtain them in any length you need and the actions can't be beat. Fabrique National in Belguim is my source for Mauser actions these days. I buy them complete less trigger for about 90 bucks. hope this helps. Shoulder angle and throat lenght will be the determining factor in whether you use a short or standard action length.0
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