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New 30/375 wildcat
- Thread starter elkaholic
- Start date
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elkaholic
Well-Known Member
Thanks Woods, I'm going to get the ball rolling tomorrow......Rich
Trickymissfit
Well-Known Member
with what you said in your post, and the idea of using a forty degree shoulder; the case length will actually shrink about .035" when fire formed. Also it seems like I read somewhere (I don't have any load data) that the Ruger RCM case is actually based off of the .300WSM case. The Remington SAUM case is a little longer than the WSM case, and the Dakota is even longer. It's going to take several dies to get where you want to get. I'd for sure start at .375, and then drop down to .338, and finish out at .308. Gonna need a press with a lot of power. Would probably be better with a 30 degree shoulder to form 35 & 40 degree shoulder really demand a lot of pressure to move the shoulder back). Would probably be nice to have a junk barrel laying around to fire form the brass with a much longer neck reamed in it. Then after fire forming you could trim the neck to the correct length to fit the desired chamber. I'd also anneal the heck out of the brass before even starting! Don't worry it's gonna bee too hard when you get done.
gary
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elkaholic
Well-Known Member
I'm going to get the reamer started tomorrow and talk to Hornady about dies. I plan on checking with them to see if I can get a deal on ordering multiple dies. If any of you are interested in this build, let me know right away.......Rich
p.s. with the throating on this reamer designed for a 225 grain bullet, I fully expect close to 3000' with a 28" barrel. This with a bullet of probably 370+ G7 b.c.........Rich
p.s. with the throating on this reamer designed for a 225 grain bullet, I fully expect close to 3000' with a 28" barrel. This with a bullet of probably 370+ G7 b.c.........Rich
Trickymissfit
Well-Known Member
didn't realize there were drawings in the thread, so disregard my post as it's not even close. Looks to me like a .300 Dakota is the best place to start as it would require the least about of rework. But alas the case diameter is .010" smaller. Am I right?
gary
gary
I see what you mean now. So yes it's probably real close to .346.
Since I wasn't involved in the reamer design I didn't care what the dimensions were. Sorry I don't know what the neck length of the reamer is. I don't have any of the unaltered 375 Ruger cases left to measure.
elkaholic
Well-Known Member
The Dakoa is a .545 case head. I thought about just building a Dakota but brass is very spendy. I think this Ruger design will work just fine now that we have a game plan......Rich
Trickymissfit
Well-Known Member
I ike what I've seen in the RCM case, but also think I'd at least opt for a .33" neck length and a 35 degree shoulder. Have always felt the .300 Ultra mag to be a miss designed idea from the start. Just way too much overbore. To me the ideal case would be about 2.25" long with the .33" neck and a 35 degree shoulder angle. Sorta like a rimless .300/.348 Ackley in many ways. Still I'm not sure a rimless .348 case (thats all a .300WSM is) would get the 3000 fps you desire.
As for pushing that shoulder back, I think your gonna see some isses with regards to the shoulder diameter. First of all it's going to take a lot of force to get there. I think I'd make up a forming die out of A2 that's about 1.25" in diameter on the Wilson concept. Then do them in an arbor press (not the ones for reloading) to get them fairly close to what you are seeking. From there, you can finish them out in your reloading press with the dies you desire. I built a set like that once a few years back out of 4150 pretreat steel, and had them nitrdie hardened for a .035" case wall. In a small 17 ton press it was easy, and the cases came out very well (they were much small 30 caliber stuff). Takes a little more time, but worth the trouble. Fireforming the cases will get old! That's where you need a few buddies that don't know anybetter! (I used my teenage sons!) If it were me, I'd find a junk .308 barrel, and rechamber it with your reamer. Then run a reamer into the neck to increase the length about .06". Then cut your cases long to allow for shrinkage.
I think you have a pretty good design in your head, and much better than a lot of the others I've seen. With the long neck and wider shoulder angle you should see a much better barrel life than the ultra mags and the WSM's if that matters much. But as much as I like it, I think i'd want it in 34 caliber.
gary
elkaholic
Well-Known Member
Thanks Gary, I think we have the reforming issue covered. I will use my bullet making press which will exert 60,000 psi or more. I think by the time the sizing is completed, there will be very little fireforming to do. Even the 40 degree shoulder will be formed in the third step and the fire forming will simply blow out .005- .007" of body taper. I think length shrinkage in this case will be VERY minimal. This design will be throated for my 225 grain bullets, so the throat will be sufficiently long so as not to take up case capacity........Rich
elkaholic
Well-Known Member
There was considerable discussion about that earlier in the thread. The short answer is: way too much case capacity and coal too long.........Rich
Rich,
My brother measured the case length of a factory loaded cartridge at 2.570".
He estimated the case neck to measure between 0.290" and 0.300", based on his estimate of the true location of the case neck to shoulder joint - from there to the end of the case neck.
Again these measurements were collected from a factory loaded 375 Ruger cartridge from a box of ammo stocked for sale in his gun shop.
Sounds like a fun project.
Paul
My brother measured the case length of a factory loaded cartridge at 2.570".
He estimated the case neck to measure between 0.290" and 0.300", based on his estimate of the true location of the case neck to shoulder joint - from there to the end of the case neck.
Again these measurements were collected from a factory loaded 375 Ruger cartridge from a box of ammo stocked for sale in his gun shop.
Sounds like a fun project.
Paul
elkaholic
Well-Known Member
Thanks to all of you for your interest and helpful suggestions. A special thanks to Phorwath for putting in a considerable amount of time in helping to calculate dimensions, etc. I will keep everyone posted as the project continues........Rich
elkaholic
Well-Known Member
Here is an update on the 30/375 S.I. I managed to round up two boxes of 375 Ruger brass from cabelas. My 375 R full length die and my 338 RCM full length die arrived and I set about to see how the reforming process would work. I cut .080" off of the 375 die to start with, lubed the case with Unique, and one easy stroke with my bullet press and the shoulder was moved back. Next I ran the case thru the 338 RCM die, and once I got it just right, No problem there. It was critical not to get back into the shoulder again so it didn't colllapse. Next step was to run it thru a 300 SAUM die with the same result as the 338, No problem! It seems that the best way to final form the case will be to push the shoulder back slightly farther than the case will end up after fireforming. This will allow the shoulder/neck jct to be slightly forward because at this point, It will still be 30 degrees. Once I get the rifle chambered, it should be easy to get the shoulder just far enough back so that the case headspaces at a point on the shoulder just above the shoulder/neck jct. Fireforming at this point will only have to change the shoulder angle to 40 degrees while blowing .004" taper out of the body. Another option would be to use my 30/375 S.I. die (when I get it) to neck down to .308 and form the 40 degree shoulder, but I'm not sure this is the best approach since I still have to blow out the body. We'll see which works best? The case length presently, after the above sizing steps, measures 2.586", a .013" increase over the parent case. My reamer is 2.590", and the case should shrink to around 2.580", when I fire form. The O.D. of the neck with a bullet seated measures .338" which is exactly the reamer size so this should work nicely for turning the necks down uniformly to .335". The end result will be a case with a .330" neck, a 40 degree shoulder, and only .011" body taper. The COAL with a 218 grain SXR seated to the lands will be around 3.75". This will position the rebate at or near the shoulder/neck jct. so the case capacity will not be reduced. The throat has .215" freebore. This makes for "one sweet looking cartridge" which will easily fit in the long Wyatt box. I will try to post a pic of the case soon and will keep everyone updated on future progress.
