New 2020 Project: Need some THF help on my wildcat design

Found a few of these cases at a garage sale in an old coffee can. They have no markings so I don’t know what they are. The first thing that struck me though, this would make a great parent case for a new Texas Whitetail round! For all the THF experts here, I have a few questions about wildcating & your suggestions would be welcome.

• What cartridge is this & where can I get more cases? I only have 4. With the short neck I’d guess it must be a Winchester case (?)
• I was thinking about doing a straight neck down to 6.5mm or should it be AI’d right off?
• I was thinking about calling it the 6.5 Incredimoor. The case head is as big as a 50 cent piece so if it ever went factory, they could stamp the name on the case head with no problems. Any thoughts?
• Would Quickloads give me some good starting loads? I have a lot of Varget on hand and as everyone knows, it pretty much works in everything.
• I don’t have a good rifle like a Tikka or CZ to start with, but I do have an old Rem ADL in 7mm Mag I could experiment with. Would it be hard to open up the bolt face on this rifle? Where can I get a new extractor? It’s the pop-in ring type. I won’t worry about any magazine issues for now.
• Dies may be a problem. Could someone with a lathe hollow-out a Creedmoor die to work? Or maybe something bigger & get a custom neck bushing made? I’m thinking an 8 ga or 10 ga shotgun shell holder would work if I can find one. (I’ve been checking & it seems that Midway never has anything I’m looking for!)
• I’m a little confused by the primer. It looks like the whole thing could be punched out and a shotgun primer used. Or should just the middle primer be punched out & a small rifle primer be used? Whatever, for sure, I’ll use a magnum primer.
• Chad, If you are reading this, could you develop a “Speedmoor” load version for this round? If so what would it cost per round & what would be a minimum order?
• What barrel should I get? I was thinking maybe one of those carbon fiber wrapped jobbers to keep the weight down. For sure it’ll be muzzle threaded for a suppressor to quiet it some.
• I figure I’ll start with a Berger 156 gr EOL Elite Hunter. Don’t know the velocity yet (any guesses are welcome) so it’s hard to figure the twist? Would a 1-in-4 twist be too aggressive? Would this bullet be okay for deer - even BIG South Texas deer? .

I most appreciate any input from the bullistic experts here on the THF.

BTW: J/K. Here is wishing all THF members a prosperous & fun & safe 2020 NEW YEAR! I have a lot of new “real” projects to finish up & some new ones on the horizon to start. I love Texas & really enjoy all the Texans, both native & those in spirit, that share this forum. Let’s keep the anti’s at bay & have a great & safe 2020 enjoying all our shooting sports. God Bless Texas!

It ought to fire good outta here

I would go with a 500 grain .458 bullet and call it the .458 Bustyurass.

20MM cannon necked down to 6.5, very funny post but yes, there's someone on here who would want it. It would be the guy, who as a kid, always pumped his pellet gun 15 times instead of 10.

Here ya go, not as cool named or read, but good place to start working from. 20mm shoulder moved back a little and necked down to .510 to use 50 bmg bullets.



rifle chambered for it on the left in this pic and the small rifle on the right is chambered in 50BMG.


The 50-20mm was said to push 750gr A-max bullets at 3650fps so about like a 22-250 shoots a 55gr bullet

I pumped mine 20

yes I want it shoot and grind a pig at one time

Good luck finding the parts once they are ground....

Spread a 20'x20' plastic tarp under the feeder...

Me too.