My new wildcat 6mm

[Hotolds442]

Jim at Apache will soon be building a barrel for my next build, a 6x55 Improved 30 degree. It uses the same 6.5x55 Swede Lapua brass Dean is using in his .22 Eroder. At $70 per hundred, this brass is hard to beat in strength, tolerance, and price. I started a trial run of necking the brass down to 6mm by using a gutted 243 Winchester sizing die, but the body was a bit too large so I stopped after the first trial round. I was about .100 short of completely sizing the neck, leaving a donut that would have made chambering impossible. I had a set of 6mm dies I had no use for, so I took the sizing die to work and turned it down to the body/shoulder junction. The first 100 rounds are now neck sized to 6mm with no issues and no donut at the junction. This round should easily top the 6mmAI, pushing a 105 AMax somewhere in the neighborhood of 3400-3500fps, and should run the 75's around 4000. I'll start building fireforming loads once I get the barrel from Apache and the headspace gauges from the big "M". The 6br sizing die will neck size, and bump the shoulder if needed, but with it being an improved round, I may have to have dies made for resizing the larger body, we'll see once things start coming together.

[scope eye]

That chambering will defiantly be my next 6mm barrel.

Dean

[Hotolds442]

http://i1276.photobucket.com/albums/y471/chevypowrd/Rifles/07B7A6BA-CEF1-43BF-9954-B418C9D0FCD8_zpsma0nkwwv.jpg
223-64gr Berger HP, 6x55-105 Hornady HPBT, 6.5x284-123 Hornady SST
The 6x55 is not the improved 30 degree version and still needs to be fireformed. It is also .005 shorter than a Savage 308 length magazine box.

[Savage6x284]

Jim at Apache will soon be building a barrel for my next build, a 6x55 Improved 30 degree. It uses the same 6.5x55 Swede Lapua brass Dean is using in his .22 Eroder. At $70 per hundred, this brass is hard to beat in strength, tolerance, and price. I started a trial run of necking the brass down to 6mm by using a gutted 243 Winchester sizing die, but the body was a bit too large so I stopped after the first trial round. I was about .100 short of completely sizing the neck, leaving a donut that would have made chambering impossible. I had a set of 6mm dies I had no use for, so I took the sizing die to work and turned it down to the body/shoulder junction. The first 100 rounds are now neck sized to 6mm with no issues and no donut at the junction. This round should easily top the 6mmAI, pushing a 105 AMax somewhere in the neighborhood of 3400-3500fps, and should run the 75's around 4000. I'll start building fireforming loads once I get the barrel from Apache and the headspace gauges from the big "M". The 6br sizing die will neck size, and bump the shoulder if needed, but with it being an improved round, I may have to have dies made for resizing the larger body, we'll see once things start coming together.

Neat project, wildcats are fun.
What's the case capacity of the cartridge?

I don't know what length barrel you have nor do I know your tolerance of high pressure but I don't think you'll get close to 3500 with a 105 in a 24-26" tube at anything below the mid to high 70's in pressure. A thirty inch barrel would get you there at sane pressure levels but who wants to tote a heavy 30"+ tube around?
I'm thinking the high 33's or the very low 34's with a 24" tube operated at <66,000psi.
Even the Lazzeroni 6.17 Spitfire with it's ~74gr capacity won't usually break 35 in a 24" tube until pressures are 71K plus. Even then only one or two powders get it to 35.

I'm an inveterate speed freak but I do try to stay under a measured (Pressure Trace) 70k.

A 105 Amax whistling along at 3400fps is definitely nothing to sneeze at!

[scope eye]

The case capacity is 58gr, and with 105gr Amax's I get 3300fps out of my 243AI and 3600fps with my 6-06AI so that should fall right in between, both of mine are 12 twists so that helps but still, that's the beauty of the Lapua brass it is good for pressures in the mid 70s before it starts showing signs of pressure.

Dean

[Savage6x284]

The case capacity is 58gr, and with 105gr Amax's I get 3300fps out of my 243AI and 3600fps with my 6-06AI so that should fall right in between, both of mine are 12 twists so that helps but still, that's the beauty of the Lapua brass it is good for pressures in the mid 70s before it starts showing signs of pressure.

Dean

What is the tube length?

What's the capacity of your 6mm-06AI?

I have never felt uncomfortable pushing 70k in any, well maintained, quality bolt action.
That said, when you're working with compressed loads strange things happen now and then.
Shooting a string of twenty which all measure close to 65k as measured with the Pressure Trace it surprises you when the next cartridge using the exact same load suddenly registers 77k!
This is inexplicable but it happen often enough that I'm wary of routinely loading to much over 70k.

I will add that although the brass is considered the weak link which warns you of too high pressure the rifle itself is also subject to the added strain. Many rifles will handle 75k every day for generations but some otherwise stout rifles will fail due to the added strain. Could be a metallurgical problem, a manufacturing problem, or a maintenance problem but shrapnel at the range or in the woods is something I always try to avoid.

[scope eye]

Barrel length is 26" I don't know what the case capacity for they 6mm06AI as far as water is, but I can fit 75gr of CFE223 into a case.

Dean

[Savage6x284]

I'll be happy to nudge 35 with the 105 in my 24" 8 twist 5R Rock in 6mm-284.

Mid 34's would be fine too but I have a problem with liking to see bigger numbers on my chronograph.

I'll likely stop when my PT records a fairly consistent 70k.

[Hotolds442]

I do believe I said it should push the 105 AMax somewhere in the neighborhood of 3400-3500 (tel:3400-3500) in the first post. I have no idea yet where it'll end up. So what if it only turns 3400. It's not like I'm trying to build the biggest, fastest 6mm since the invention of black powder. All it needs to to for me is puff coyotes with a resounding thud. They won't care if it's 3400 or 3500 either.
My local Sportsmans had 8 1lb cans of H1000 on the shelf today, I grabbed two so I'll get to work up some loads with that, also. 100 rounds of Lapua brass is neck sized to 6mm, another 100 on the big brown truck. Hopefully the barrel will be here next week so I can start working up loads for it. I'm getting antsy!

[scope eye]

"It's not like I'm trying to build the biggest, fastest 6mm since the invention of black powder"

No that's my job,LOL

Dean


PS: I am sure it will make for an awesome round.

[Hotolds442]

"No that's my job,LOL"

Dean


So I've noticed!
Until you neck that 20mm round down to 6mm, you've got nothing but pop guns.

http://i1276.photobucket.com/albums/y471/chevypowrd/Rifles/439a35ae766d329eade12708805ed6d3_zpsef228121.jpg
From left to right: .223, .338 lapua, 50BMG, 20MM Vulcan

[Savage6x284]

I do believe I said it should push the 105 AMax somewhere in the neighborhood of 3400-3500 in the first post. I have no idea yet where it'll end up. So what if it only turns 3400. It's not like I'm trying to build the biggest, fastest 6mm since the invention of black powder. All it needs to to for me is puff coyotes with a resounding thud. They won't care if it's 3400 or 3500 either.
My local Sportsmans had 8 1lb cans of H1000 on the shelf today, I grabbed two so I'll get to work up some loads with that, also. 100 rounds of Lapua brass is neck sized to 6mm, another 100 on the big brown truck. Hopefully the barrel will be here next week so I can start working up loads for it. I'm getting antsy!

As I said in my initial post.

A 105 Amax whistling along at 3400fps is definitely nothing to sneeze at!

Try some Magpro if you can find it. It consistently gives me the highest speeds in cartridges of this approximate case capacity. Being a ball powder it also meters superbly.
A bit sensitive to very high ambient temps as are most ball powders but nothing dangerous or potentially catastrophic about it. One of my favorite powders.

[FW Conch]

Hotolds442, just curious, why did you go for the 30 degree shoulder angle ?

Thanks.........Jim

[Hotolds442]

The 30 degree shoulder comes from the 6BR reamer used to cut the chamber, run in an additional .580 or so. So basically this is a 6br x 55mm.

[sharpshooter]

You guys are amateurs!
http://i2.photobucket.com/albums/y48/sharp-shooter/bigguns.jpg (http://s2.photobucket.com/user/sharp-shooter/media/bigguns.jpg.html)

[Hotolds442]

Now we're cooking!

Dean will be here shortly to droll all over them.....


ETA: the cartridge on the right has a case diameter larger than the threads on a small shank Savage action. I'm guessing 20mm Vulcan necked down to .224

[scope eye]

[QUOTE=Hotolds442;246907]Now we're cooking!

Dean will be here shortly to droll all over them.....


I'm not Worthy I'm not Worthy.:hail:

Signed
By a Mere Peasant

[FW Conch]

Thanks Hotolds442. I figured the 30 degree shoulder came from something like that.

"Not that there's anything wrong with a 30 degree shoulder"! ;-)).........Jim

[Hotolds442]

The barrel is in transit!
I hope to have a range report on Thursday if everything goes as planned.

[scope eye]

The barrel is in transit!
I hope to have a range report on Thursday if everything goes as planned.

I expect a full report on my desk in the morning.:cool:

Dean