Is it possible to change the extractor on a 307 so as to shoot 308 rounds? Would the pressures be too high? What about on the 356 Win to use 308 cases, or maybe even 358 win loads? I'd be using a Win Big bore. Buying one or the other either way. Thanks bg
Check an older thread on this forum entitled "336 in 358. John A had a Marlin 336 in .35 Remington modified to shoot the .356 Rimless, i.e. 358 Winchester loaded down to .356 pressures. Said it was done by Ronn Carmichael of The Gun Shop in Lancaster ,CA. 661-942-8377. Said he got 2400 fps with Speer 220 grain FN bullets and 1 and 3/4" grounps at 100 yds. Of course, the .35 Remington is a rimless round in the first instance and a slightly different type of modification may be required in going from the rimmed .356 to the rimless .358 casing. I've read of guys shooting .358 cases in their .356's but they didn't extract too well. Don't know why your conversion shouldn't be possible, but why not just stock up on a supply of .307 or .356 rimmed cases.
Boyd Slusser (same thread) had a Marlin 336 .35 Remington rechambed to .356 Winchester by SSK.
Sounds like you're looking for the .356 Rimless in the first example. Good luck with your project.
A quick check of the Accurate Arms #2 Loading guide shows that all 4 cartidges (.307 Win/.308 Win/.356 Win/.358 Win) have a listed SAAMI Maximum Average Pressure of 52,000 C.U.P.
However, the brass is not the same internally. The .307 and .356 brass is thicker and able to handle the pressure better with less support from the rifles action. The .307 and .356 were designed to be shot in Lever Action rifles that had rear (springy) locking lugs. The .308 and .358 were designed to be shot in bolt action and semi-auto actions that have better (stronger) lockup such as with front locking lugs. The .308 and .358 are better supported by the rifles action. I think that it would be a bad idea to substitute .308 for .307 and .358 for .356, especially when .307 and .356 brass is readily available.
If I'm way off base here I'll accept criticism but it just seems like an unsafe practice, especially with full throttle .308 and .358 factory loads, or hot handloads. I think at least the case life would be very short, even worse than .307/.356 case life.
You're absolutely right Dutch. If you're going to use .308 & .358 brass you have to limit loads to .307 & 356 pressures. The advantage of using .308/358 Win brass is that it's cheaper and more widely accessible than the rimmed rounds.
Absolutely! As a matter of fact if it is at all possible I suggest you buy both. Trust me that long after your wallet has stopped hurting and your ears have stopped ringing from the little lady's screams you'll be glad you have them. I have one of each and they are my two favorites.
I too have considered rechambering my .35 Marlin 336 to either the .356 Rimless (.358wcf brass loaded to .356wcf specs) or outright conversion to a .356wcf. To convert the rimless .35 to .356 rimmed, the easisest way is to get a .30/30 bolt which is set up to handle the rimmed case.
Either way, after doing some load development and chronographing, I've got a load in .35-Rem. with the 180gr Speer that runs 2,500fps and extracts effortlessly, and a 200gr Rem.Cor-lokt thats running 2300-2350fps. I can't now justify the modifications, as the improvement in power and trajectory dosen't justify the cost.
We really should be clammering with Marlin to start a "Custom" or "Classic" series with a different caliber offering each year; some in "New" cartridges such as the .356wcf, or a 7-30 Waters (I want one in each !), others in oldies such as a .25-35 (want one of these too).
Especially, if anyone is listening; is a 20" half magazine Stainless Steel-with gray finish (like some of the Ruger SS guns), with either a synthetic stock (camo) or laminated, and no blast ports please!! in .356wcf. Also a 7-30Waters too !!
There is no way on God's green earth you can run 2300-2350 fps from the .35 Remington at anything close to sane pressures. Not saying you can't do it, just not at SAFE pressures. To do this you have to be running pressures well in excess of what even the belted magnums use. Something is gonna come loose on you eventually. I hope you still have all your fingers and eyes after it does.
Thanks for the info again. Its obvious that ya'll are much wiser than I am on the subject and I apologize for being slow, but isn't 52,000 cups 52,00 cup? Will the rifle know the difference from a 308 and a 307? It seems the cases absorb up some of the pressure and and the 52,000 cups remain the same? Its just trivial now, becuase I'm going to get one or the other and use the correct loads in each, but I'm a sucker for good pressure/balistic problems. Also, it seems that the 307 and 356 are hard to find here in my neck of the woods in TX. Gunshow this weekend and will check it out. Lastly, from what I read, it isn't much of a problem to convert a 35 Rem into a 356, correct? Need 30-30 bolt and rechamber the bbl. what about putting a new 356 or 307 bbl on a 30-30? Seems I can get one of them for a song here. Thanks again. bg
I have run 308 brass through my 356 to see how it would work. They would cycle fine and extact ok as well. The only problem I had with them was since there was no rim, one out of about 25 or so did manage to slip under the cartridge lifter and tie up the gun.
Check sixgunner.com for some articles on the 356 by Paco Kelly. I believe he altered his extractor slightly on his 356 to use 308 brass. He would fireform military 308's to the 356 chamber and reload it with 356 loads.
I have also read an account in a special edition magazine called Leverguns where the author fired a 358 in a 356 Winchester with no ill effect to himself or the firearm. While I wouldn't reccomend it, it is interesting to note that the 356 and 358 have the same working pressures (as listed in the Speer Manual). However, to function through the 94 action the 358 would have to have the bullet set further back into the case which would raise pressures dangerously with the same powder charge.
Of course both the 308 and 358 as factory loaded are too long to function in the Winchester 94 action! In a pinch (like no factory brass at all) I am sure that 308 could be made to function in either action.
FYI - As of a few weeks ago, midway had .307 brass on sale for under $15 per 50. I think the sale is over, but they still have plenty of brass and give a better discount if you buy large quantities (I think a bag of 500 is $132)
I have both a .307 and .375 (newly aquired) and jump on cheap winchester brass whenever I see it.
You can also fire-form either round from .30-.30 brass (I have been told) and there are several internet companies that sell fire-formed brass.
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