Help with 375 whelen

[Stephen Cohen]

I have noted that several of you guys have the 375 whelen Improved. I need help with my case forming, and loads. my Rifle was headspaced with 35 whelen gauges as I was useing 35 whelen brass to form, now the problems are that the R-P cases Im useing vary so much I have difficulty getting a uniform batch of cases formed. some have bad headspace issues, backed out primes and are not a good crush fit in chamber. My forming load is 125gr Hornady SP and 57gr of Mulwex 2206H which is H4894. I was given a batch of Lee cast 250gr FP boolits, I noticed I can seat them out to touch rifling and make a good crush fit, I need a load that will form good cases and can be used as a good hunting load with said boolits. Powder selection is limited in this country to mainly Mulwex, the two powders I use most are Mulwex 2206H which is H4895 and 2208 which is Vargent to you guys, would these be suitable . If so what load or should I look at a fast pistol powder, Im not a lover of small charges in large case though. Regards Steve.

[runfiverun]

both of those powders would do well with a case filler.
if you find nothing else 35 whelen loads for a similar boolit weight is where i would start.

[paul h]

I had a 35 whelen ackley and had the same issues with fireforming brass. Not sure if the gunsmith set my shoulder too far forward, or the M98 firing pin was overzelous in starting combustion, but I had many cases with protruding primers.

I found Varget, or your 2208 a great powder in the 35, and figure it should work just as well in the 375. I would advise using a bullet you can seat solidly into the lands for a good crush fit when fireforming. Top end non-ackley loads will give you a well formed case. If you're using a 270 gr jacketed bullet, 55gr of varget/2208 should be near a top load in the non-ackley chamber.

[Stephen Cohen]

Thanks guys, will give it a go.

[Harry O]

I have a couple of 9.5x57 Mannlicher-Schoenauer rifles and have to make my own cases. It is a slightly shortened .375 Whelen (9.5mm and .375" are the same). I had the same problem trying to make my cases out of 8x57 Mauser cases. There are three ways I have used to solve that problem.

The problem is that enlarging the neck does not leave enough shoulder to hold the case in place when the firing pin strikes the primer. The firing pin pushes the case forward until it is stopped by the extractor. That leaves it short from the base to the shoulder. That is the equivalent of excess headspace.

The first solution is not available to you. I now use .35 Whelen brass to form my cases and then shorten them. Because the shoulder is moved back into the larger diameter part of the case, there is enough shoulder to hold it when fireforming. It also helps to back off the sizing die a turn or two to make the formed case a slight press fit when chambered.

Another way, when using 8x57 Mauser cases was to enlarge the mouth to 0.400" first, then neck it down to 0.375". Again, by backing off the sizing die, I got a shoulder strong enough to hold it in place. There were quite a few case losses necking it up to 0.400" and then back down, though. I don't do that any more.

The last way was to get a 300gr RN Hornady bullet and seat it way forward to jam it into the rifling and hold it in place. I used 8x57 Mauser cases for that without going to 0.400" first. That worked, but the bullets were too expensive, even when I found them on sale at gunshows. Note that the 270gr Hornady bullet is too small in diameter in the forward part of the bullet to work.

What I do now, using the .35 Whelen brass is (after expanding the neck to 0.375") put in a primer, put in 13gr of Red Dot (it is one of the Lee scoops), fill the rest of the case with shot buffer, and press a wax plug in the mouth. There is almost no case loss and very little cost since I am not using a bullet. Remember to reset the sizing die back to its original position when loading them for real.

[Stephen Cohen]

Thank you Harry O, seems we are on same page, I have loaded some 35 whelen shells with 250gr cast which give me a crush fit, after I use these I will neck size enough to load 270gr Speer jacketed to a crush fit and use them on up coming pig hunt, I should have well formed shells after that.