It's Alive. My New Wildcat

[WSMNUT]

Last year we set out to make a new wildcat out of what I felt like was a necessity. Let me explain why first and then you will see how my tiny brain works and what we came up with.
During the last 600 yard F-Class match of the year at WhiteHorse range my wife decides she wants to shoot her first match. Being the gentleman that I am I let her shoot my 6BRA (that I planned on shooting) that weighs 21 lbs and is probably one of the better shooting rifles I have ever made for myself. I hurried to finish my 284 Shehane and work up a pretty good load for it. During the first relay I shot a 200-13X and my wife shot a 199-10X (again her first ever time shooting over 200 yards)
Next is where the tiny gears started turning. After the pit change the wind got crazy switchy and a rain storm blew in. I shot a 195 or 196 ?X and my wife shot a 190 ?X. The wind was so bad and switched so much that everyone had a bad relay but the 6mm's got hammered. Even my Shehane was sending unexplained bullets in odd directions.
Knowing that I really don't want to shoot my 284 Shehane at 600 yards all of the time I started thinking about what caliber to chamber next to try to have a better edge since reading the wind still mystifies me. I thought of the normal caliber 6.5-284 which I shot for a couple of years and love but hate the barrel life, I thought of a 6x47 but again with my poor wind reading abilities and just watching all of the dashers and BRA'S getting hammered by the wind I kept digging. 6.5x47 came to mind but I wanted more HP.
I shifted my focus on the 260 Ackley since it has become one of my favorite hunting rounds. I started pulling up my reamer prints and comparing it to some of my other reamers. I kept going back to the 6BRA and 6.5X47 prints for ideas and it hit me.
Shorten the body of the 260 AI .040 but keep the overall length the same which will lengthen the neck of the case .040 giving it roughly the same neck length as the 6BR and 6.5x47 which have been two of the most accurate cases ever designed.
Next was trying to figure out how make and form brass. Not wanting to wreck any good Lapua brass I had some Hornady 7-08 brass that I policed. I used a 6.5x47 Die and to my surprise it was very easy to push the shoulder back .040 without it collapsing it.
I contacted Dave Kiff at PT&G to help me with the reamer. He suggested 293.5 for the neck diameter that way the neck can be cleaned up where the old neck/shoulder junction was and we decided to go with .188 freebore since it has worked so well with the 6.5-284
The important question is what to name it. After some deliberation I decided to call it the 260 DeVito Imp. I had just recently seen a commercial for the movie Twins and it was fresh on my mind when I thought about the name of it. I also gave some consideration to calling it the 260 Zackley since my name is Zack but thought 260 DeVito was a more fun name.

Now for the particulars.
Does it shoot? Oh yeah, It shoots like its pissed off at the X ring.
Is it fast? Yes sir. Getting 3,000 FPS with a 140 is not a problem using H4350. I am sure with powders like RL26 you could get some unruly speeds but I love H4350 and I will just stick with it for now. I have some faster speeds recorded but the BIG accuracy/speed node is just over 3,000 FPS with my 30" Hawk Hill barrel and its not hard on the brass to get there.
I am currently using Peterson 260 Rem Small Rifle Primer brass.
I use a Redding 260 Ackley bushing die that I set up in the lathe and took .040 off
I just received some 156 Berger Extreme Outer Limit bullets from Blue Collar Reloading and plan to shoot some 200 yard groups this weekend. If the weather holds off I will post some data on that bullet too as it seems like it would be a great combo.
I do not know the barrel life yet but we're expecting north of 2,000 rounds maybe 2,500. Its around 4-4.5 Gr less powder than a 6.5-284 and 4-4.5 GR more powder than a 6.5X47 so expect barrel life to be somewhere in the middle of those two rounds

I was hoping to shoot my first match with it last weekend but since the China Virus shut that down I was not able to get any match data.

Here's some side by side pics of a 6.5X47 (left) 260 DeVito Imp (middle) and a 260 AI (right) and also the reamer print in case you want more details.

 

[Plumsask]

I shoot a 6mm ackley Imp. On an 8 twist. Made good brass for it using a paul Bike shoulder set back die from 30-06 lapua. The 6mm rem has a long neck to begin with as well. What made you want a longer neck? Barrel life? As I've heard it helps calm down the turbulent gasses.

 

[WSMNUT]

I thought about the neck length on the 7x57 but if memory serves I had to go .080 to get there. I didn’t mind that but wanted to try this first.
I wanted the neck to match the 47 and BR cases since they’re so accurate. Just thought it would be a good foundation to start at.

 

[Plumsask]

Makes sense, I have yet to dive into the BR/br variant family of cartridges. I'm sure it is in my future.

 

[TAJ45]

I had a Wild idea meself several years back. My savvy Bud and I collaborated and came up with an XC Long Neck. Palma squeezed back to abt 49mm w those fabulous PBike dies. We both feel the turbulence point being buried should help with throat erosion. Our necks ended up at .400 length. Nodes at 3200 - 3350 per Oehler. It was 800 rds before the XCaliber stopped shooting zeros w the plain 107 Sierras. Only ones and low twos now. Minimal throat wear as well. Case life is stellar.
Probably reasonable to assume a fair amount less recoil than the DV. Kinda fun to have an idea and bring it to fruition, eh? Nice work.

 

[bsumoba]

Interesting. Did you ever consider the 6.5 creedmoor? Its was the presumptive go between for the 6.5x47 and 260. At 42-43.5 gr of H4350, a lot of guys are getting good numbers with 140 hybrids in the 2900-2975 fps range in the open barrel lengths. I see you are getting faster speeds than that, but the question will be at what cost to barrel life as you had mentioned as well as a secondary step to form cases.

 

[WSMNUT]

Yes I considered the Creedmoor but not for long. I didn’t know you could get 2975 with a 6.5 Creedmoor with 4350??? I’ve not heard of anyone doing that. I guess anything’s possible but the guys we shoot with using Creedmoor’s are barely getting 2900 with there’s. I think they’re getting Garst we speeds using 26 but I’ve not tested with it to compare

 

[bsumoba]

Yes I considered the Creedmoor but not for long. I didn’t know you could get 2975 with a 6.5 Creedmoor with 4350??? I’ve not heard of anyone doing that. I guess anything’s possible but the guys we shoot with using Creedmoor’s are barely getting 2900 with there’s. I think they’re getting Garst we speeds using 26 but I’ve not tested with it to compare

Long freebore and small primer pockets help quite a bit. There is enough neck there to push the case out.

 

[flatlander]

I did something very similar to your 260 DeVito Imp a few years ago, only went with a 30* shoulder. My reamer print is within a couple thou of yours in most dimensions, but the neck of my print is only .321" long. The 1st bbl I chambered was a 26" sendero contour that went on a trued M700 w/PTG custom bolt in a McMillan A5 stock for some PRS-style matches I was shooting at the time. Was very happy with that rifle, shooting S123MKs & B140VLDs, using IMR4451 powder. That 1st bbl just quit shooting at something over 1700rds, though the throat still looks pretty good through the Hawkeye. I just recently did another bbl for one of my Bighorn TL2-SA actions in a Manners T4A stock - have just barely gotten the bbl broken in; haven't chronographed anything out of it yet to see how it compares to the 1st one. I felt that the 1st bbl was easy to tune, a lot more so than the 6.5x47s I've done. Hope you have as much fun & success with yours as I have had with mine!

 

[TAJ45]

Flatlander: What kind of velocities were you getting at the accuracy nodes?

 

[KMart]

OP, doing a wildcat is fun. But you need patience waiting for all the stuff to line up properly. I did a couple of rifles about 2 years ago now and it was fun. They are both 25 cal and nothing real radical. It is really nice when you get through and they shoot well
I have toyed with the idea of doing something similar to you with the 260. Your design is similar to the 6.5 SLR that was somewhat popular a few years ago, but it had a 30 degree shoulder.
Good Job!

 

[Kurz]

I've always found the 6mm and the 6.5mm Super LRs to be very easy to make and to tune. I'm puzzled by their lack of success except for the proprietary dies which are expensive. They solve the drawbacks to the parent cases, the .243 Win. and the .260 Rem. You create a longer neck and 30 degree shoulder with the die for a better balanced cartridge. The ones I've built have been very accurate and easily tuned.

 

[Liven The Dream]

Ran a 6 Remington case 1-7.5 32" Barrel set-up for 2 Barrels.
H4831 SC 115 D-Tack at 3040 . 1000 yard Prone Rifle .
1750 -1840 Barrel Life ??
Just for some info .

 

[carlsbad]

I've been thinking about something to shoot 144s along that line. What you have described is the 6.5mm SLR. --Jerry

 

[TZaun]

Nice job @WSMNUT. Sounds like a fun project and even better that it’s a shooter!! I’m just diving into something I’m calling a 25 SLR Imp. Built it to shoot the 131 Blackjack. I was surprised how easily one pass through a Whidden die pushed the shoulder back and changed the angle to 35°.

 

[WSMNUT]

I've been thinking about something to shoot 144s along that line. What you have described is the 6.5mm SLR. --Jerry

It’s close but not quite the same it’s with a 40 degree shoulder and a little shorter neck length.

I hadn’t actually researched the SLR and didn’t know about it until recently.

 

[WSMNUT]

Nice job @WSMNUT. Sounds like a fun project and even better that it’s a shooter!! I’m just diving into something I’m calling a 25 SLR Imp. Built it to shoot the 131 Blackjack. I was surprised how easily one pass through a Whidden die pushed the shoulder back and changed the angle to 35°.

That’s a cool idea. I’ve played with the 25 some. I did a 25-243AI last year and I’ve built a few 25 Creedmoor’s and 25-284’s for other people but when I first started shooting and then building my own guns I started with a 6.5 and I guess it just can’t get over those high BC low recoil rounds

 

[andym686]

Interesting reading Zack. As always, you have put a lot of thought into this project. Keep us updated with some targets as you get more rounds through it.
Andy

 

[std7mag]

While the Shehane is the "Ackley Improved" version of the 284 Win, has anyone thought of doing this with the 284 casing to give a slightly longer neck?

 

[Capt. Oblivious]

Nice job @WSMNUT. Sounds like a fun project and even better that it’s a shooter!! I’m just diving into something I’m calling a 25 SLR Imp. Built it to shoot the 131 Blackjack. I was surprised how easily one pass through a Whidden die pushed the shoulder back and changed the angle to 35°.

I love me some SLR, the first 2 SLR cases I had in my hand was a 25slr and 6slr imp. Was hooked on them and still want to da a 25slr in a lite hunting rifle. This 260 DeVito Imp looks like the number to me in 6.5