Just a little brain picking for those with thoughts.

[350JR]

While looking at a couple different rounds for the 375 wildcat I have on the table a couple things popped out that either just has me scraching my head a bit and/or thought some might have experiences with them so thought I'd fire this out there at the gang.

In performance, I cannot imagine this first point being any kind of issue but I did find it interesting and created some thoughts on just "wondering why" such is different.

Left to right is a 300RUM, 375RUM and 375 Ruger.

Its much more obvious than I can photograph but....even though the brass angle near the rim is the same on SAAMI specs for the 300 and 375 RUM.......it sure dont LOOK the same. I only HAVE two 300 RUM but both have the "longer" bevel above the rim. Just thought that was odd, myself, that they would be different from that on the 375RUM just from a production standpoint.

Next up is the much trommeled "neck length" subject and I am aware that for decades, if not longer, that neck lengths are considered optimum if the neck length is at least the same as the bullet diameter.

That said, if I were starting the 350JR project at this point in time, the neck would be shorter. There is no "problem" with current neck length but the fact is.....I dont use it all and wont in these super short (1.8 inch maximum brass) wildcats for deer hunting here in Indiana.

The necks on the 375 RUM and 375 Ruger are both short......caliber wise. Unless I messed up, SAAMI specs show the 375 RUM neck at .3588" and the 375 Ruger at .305"

http://www.saami.org/pubresources/cc_dr ... Magnum.pdf

http://www.saami.org/pubresources/cc_dr ... 0Ruger.pdf

While MAXIMUM case capacity isnt the main goal, "free" capacity is always nice. I thought I would toss this info out and see if any of you 375 shooters of either round have noticed any downsides.........in real life use.

This VERY short wildcat appears much more balanced out with a shorter neck than "standard" but standard don't even seem to be the SOP for the newer 375 bore rounds.

Left to right. My 350JR, 375Ruger and 375RUM.

I would ALSO appreciate it if someone could please measure the length of a Speer 235 grain .375 bore bullet and let me know what it is? I havent dumbed into a mess of them yet. :wink: Being designed for whitetail a COAL with this or similar bullet sizes is of greater interest.

Just fyi.....once again, this round is following somewhat in my former process used with the 350JR where "less costly and easier to form" is taking priority over a few grains in case capacity increase costing more in funds and time and I do realize this isnt the norm for most building one.

God Bless
Steve

 

[gerry]

Just measured 5 235 gr Speer bullets and they were between 1.05 - 1.06" in length. The 235 Speer along with the 225 gr Hornady Spire point would be excellent for what you have in mind.

 

[350JR]

Thank you, Gerry!!!

Id like to see ( or do in the future) a "bullet test" comparison on both those bullets out of this shorty.

Like what I read about both.
GodBless
Steve

 

[Ridge_Runner]

not sure if applicable but, I have shot the speer 235 gr. 375 bullet in a 12.75" contendor chambered in 375 jdj, at around 2100 fps it doesn't expand much if any unless you hit something very solid, more solid than a deers shoulder or a bears head.
RR

 

[gerry]

You are welcome Steve, I bet you could get around 2500-2600 fps which should be perfect speed for both those bullets. I did a test with them in my 375 Ruger at 2750 fps, they did milk 6 jugs in the last jug the jacket and core separated but by then the bullet would have made it through the vitals of even a big animal. Lost some of my bullets and records in moving but Guy Miner has done the same test and the Speer's did really well too. It is neat to see the results of your wild cats please keep us up to date. The Ultra Mag case will have a bit more case capacity than the Ruger but probably not by much, it will be neat to see which one you decide to use.

FWIW the short 375 Ruger neck holds bullets fine, I have yet to crimp anything and have had no issues.

 

[nvbroncrider]

In the 50's and 60's they did alot of experimenting with short necks. My grandpa was in on some of that with Rocky Gibbs. They found that you can get away with a short neck and they were very accurate. So what they ended up doing is playing with the length of the neck and would design the Gibbs cartridges which were based on the 06 with blowing the shoulder out and moving it forward until they hit the limit on the minimum neck length required to securely hold the bullet in the magazine while firing. I will try to get a picture of a 7 Gibbs up in the next few days.

 

[gerry]

Just did another measurement on a 235 gr Speer and the shank is about .430" the best I can measure before it starts to taper down towards the nose leaving around .620" that would stick out of the case. I would imagine they would vary a bit from different runs of bullets but it should give you an idea of what to expect.

 

[Ridge_Runner]

my 6.5 gibbs starts with a 270 case, after the shoulder in blown out the neck length is .308"

RR

 

[350JR]

Thanks much for all the info. A BIG help, gang!

A couple things are turning me towards the Ruger case.

As said previously, cost and PIA level do take a part in a wildcat for me.

With a couple neck and shoulder already removed RUM brass, next step was to whack off a 375 Ruger slightly above where the shoulder would be on a projected case to compare brass thickness.

While a caliper is not the foremost choice of instruments to measure body wall thickness, it does at least show the amount of DIFFERENCE comparing a couple. The Ruger brass showed a .020 thickness and the RUM?..........026!! Arghhhh!

With turning the projected wall of the neck, maybe even a little of the shoulder area being a prerequisite, with some loving annealing the .020 thick Ruger brass might be formable as is while the RUM appears it would take something hydraulically powered for forming mid case walls, at least IMHO AND......double the amount of brass needed to be turned from neck walls. Kind of a no brainer for me. Capacity be danged. Both would provide "enough" of a capacity increase over my current 350JR. Laser beam trajectories are not expected with a 375 bore.

Probably, I should stay silent on this next subject till said and done but I've spent enough time with the SAAMI specs, a few examples of the cases and my calipers to feel 99.9 percent confident this will work and do so quite handily.

Just how much the incoming form/trim and FL dies move the brass around will be the next subject to study but interestingly enough, the diameter of the Ruger brass where the shoulder will be, is within .002 of the SAAMI specs of the RUM shoulder. Pretrimmed Ruger brass, to make it LESS of a JOB, pushed in a shortened to appropriate length 375 RUM form and trim die SHOULD produce a short "Tweener" case that measures .532-.534 above the Rim and a .522-.524 diameter 30 degree started shoulder and neck length decided by my case trimmer.

Basically a 375 Ruger base and 375 RUM shoulder. Nope. Not much of a body taper but keep in mind the VERY short distance from shoulder to end of body brass. 1.25" (ish) long after deducting neck/shoulder and web/rim lengths. Measurements are guesstimates. If never taking your calipers to a case before and after using any particular die, one might find it a bit eyebrow raising. I know it was for me doing so the first time. SOME dies move brass a wee bit more than one would anticipate, or should I say I anticipated? :wink:

This single factor had me order BOTH the RCBS and the Redding 375 RUM trim die. Running FIRED brass into each will give me a closer look at end results, JIC. (Second one will be "trading stock" :grin: ) PROBLEM there, of course is the FIRED brass mentioned. Mine are new but might not be a concern. Im sure that , somewhere out there in WWW land, there is a process mentioned to "slug" or cast the inside of each form die for a closer look before deciding which I'll use before shortening. Hopefully, there will be little difference BUT, in comparing dies previously I've found as much as .004 difference between dies of different MFG. PERHAPS dies do not run symetrically WITHIN a particular company but at this point, that is moot. What I will have in hand is the only concern.

UNdecided as of yet is the mentioned neck length. Some do not feel it "safe" or works at all but, short reaming a chamber with a cartridge reamer of choice CAN produce a "short wildcat" and has been done. The single issue there is the fact that this process would mandate the .3588 long RUM neck length (unless someone out there has a RUM BODY ONLY reamer :roll: )

Thinking OUTSIDE THE BOX a bit, there IS one thing I FEEL would work to give me the shorter of the two neck lengths in a reamed chamber. (Keep in mind I have exactly ZERO gunsmithing experience). A custom reamer is, of course, BETTER yet NOT having to have one made for a single firearm (who the rip ELSE would want one? LOL!) HOWEVER.....a quick look at a 300 RUM SAAMI sheet shows a .306 neck length (recall the 375 Ruger is .305).

Completed by a HIGHLY COMPETENT smith, a "short reamed" chamber with a 300 RUM reamer (for the 1.795 cartridge) then a .375 neck/throat reamer used to open to desired dimensions? :idea: Hmmmm. WELL AWARE that most are not normally using a "cheaper is mandated" SOP, I know in advance that most here will "nay say" such an operation and state that a custom reamer is the ONLY way to go. Time will tell. Good thing I DONT HAVE a lathe and any kind of training, Eh?

IF any of the thought process above is (probably) confusing, simply put Im planning to use the bottom portion of a 375 Ruger brass, fit to the top portion of a 375 RUM die. The smaller section of the Ruger brass and larger section of the RUM dies......removed. A combo of Remington and Ruger technology.

BTW, it is QUITE all right if a few, er........some, ALL? think I'm losing it. Hardly "virgin territory". I cannot express HOW MUCH FUN this is to me!! End results of multiple compilations of facts, hours of measuring and testing all produce something MUCH needed within my life. Satisfaction (and something else to think about)!

More to come.

God Bless
Steve

 

[350JR]

After a year (almost) back up. This isn't in the crapper just yet.

The 350JR (a few posts here about the B*astardized baby mag I made for Indiana) is still laying them low here in Indiana. 1.5 seasons in use, 9 deer brown and down. Furthest any went was 45 paces. No "long" shots yet. 175 yards max to date but "bang-flop" is SO MUCH FUN!!

And back OT. 2 surgeries, 9 injections in knees, off work like 1/3 of 2012 (including when I started this) but THOUGHT I was going to be able to go back to work.......NOT! Yish. At least my brain still (sometimes) works! At any rate, issues caused a "lull" in the action on this wildcat, financially speaking and will take longer than I wanted but........stuff happens. No reason to give up.

The 375 ruger, set back shoulder and trimmed (1.8") to standard parent neck length is giving me an estimated 69 grains of h20 to neck top. That fat case and no belt, shorter (and fatter) neck compared to the 350JR made a bit bigger difference than I expected. While human error is a factor, I came out real close on the other and will not be totally disappointed if it came out a bit less.

Anyone have records on what the neck only capacity of the 375 Ruger till I can come up with some more brass? (I had a whopping ONE brass to play with). 9 grains or so?. Just estimating prematurely what kind of working capacity there will be.

Keep in mind this round will be centered around the 225-235 grain bullets with possible 250 grain trials and it's purpose is to make a 375 short mag to hunt whitetail here in Indiana (just to be different....and cause I'm weird) :mrgreen:

*Sigh* starting over as you can see. Pardon the inconvenience!!
God Bless

 

[DrMike]

Sorry to hear about the physical troubles, but glad to see you back. I'll look around and see if I have some data saved.

 

[350JR]

Thanks Doc. It's expected as one ages and pays the toll of years of heavy lifting, decades of climbing steel steps, 12 hour work shifts .....and a couple car crashes. :? I wasn't as prepared as I would have liked and it came at me too fast to do much about it but glass half full, I can hug my sons, hold my grand daughter, pet my dog and enjoy the outdoors with a little precautionary forethought so "eh!" :grin:

All in all the menagerie of government BS I deal with trying to get things set up is a bigger "pain" than anything. I've been poor before and know of many worse off so I give thanks regularly..........today especially being Thanksgiving!

The included financial situation that comes with such things is unwanted and will damper the progress on this project but perhaps it is a dark cloud with a silver lining and I don't run at it full bore and over look something too.

Once I get another set of dies (sold the ranch when the SHTF) to alter and attack things there IS a couple other brass cases I'd like to run through it......JIC!! :grin: "Making something work" INSTEAD of sinking funds into custom dies etc is a way of life I've plugged away at over 6 decades and most disagree with such, seeing big "red flags" waving everywhere but I am careful and it IS part of the entire process that I enjoy doing.

Not limited by state regs I realize that to most reading here that this super short wildcat is of little interest and seems even odder than most so any insight is much appreciated!!

A couple regulatory things I have to take care of for the feds but Ill be at this first of the year as I can.

As funds allow I will pick up another set of 375 RUM dies to shorten. The WSM family brass I think will be a bit oversized to alter but will look at such however the RSAUM brass might fill the bill. I will find a couple to play with simply because of the close OAL and "close" outside diameter (a little tongue in cheek there on the "close" LOL!).

For now though, the 375 Ruger brass appears to meet case exterior expectations but will take a LOT of reaming for neck brass out of mid case and why the short mag brass is worth a run at. I have yet to see any of the super short mag brass. Only comparing them measuring different areas of the brass (I don't always trust the drawings) and run in the die will give me any more facts.

IF I can get by without a 375 RUM form and trim die I will but it will be mandatory for the Ruger brass, maybe all considered but being hard headed, Ill break out the Imperial wax and take a look!

God Bless
Steve