New 270 boondoggle wildcat testing

[yorke-1]

This project started over a year ago and there have been a couple "complications, setbacks and minor inconveniences" along the way, but it's pretty much done and now it's time for the fun part. The initial cartridge design was based off of the 375 Ruger case but after the reamer broke while chambering the barrel, it was necessary to "adapt". What I ended up with essentially a 27 Nosler that's been lengthened by .130" so that it has the base to shoulder measurement of a 338 RUM case but the shoulder diameter and 35° shoulder angle of the 27 Nosler. The idea was to allow the use of ADG's 338 RUM brass (or any other RUM brass properly modified) but still be able to use 27 Nosler dies to neck size and bump the shoulder while waiting for custom dies to be made. Forming brass only requires necking a 338 RUM case down to 270, I used 300 SAUM and 270 WSM dies then annealed the brass before sizing it in a 27 Nosler die until the bolt closed on each case with a slight crush fit. The shoulder diameter and angle are completely formed after the first firing. Here's a 338 RUM case next to a once fired 27 Boondoggle case.

The specs on the build right now:
- ARC Nucleus action
- 28" Broughton 1-8.5" twist heavy varmint barrel
- 25" K&P 1-7" twist #5 heavy sporter
- Timney CE 2.5# trigger
- Stocky's VG2 stock w/Wyatt's bottom metal

The final specs on the build will still change as I decide what scope/trigger/stock I want. I don't hate the VG2 stock that it's in right now but the gun won't stay in there for long. I'm trying to find a sporter style stock that I like for the 25" barrel as well.

Here's a picture with a once fired 27 Boondoggle case next to some other cases for comparison. I couldn't find any 270 Weatherby or 270 WSM brass in my pile so I used a 300 WSM and 7mm Weatherby for comparison since they're both the same basic dimensions as their 270 counterparts.

270 Win, 300 WSM, 7mm Rem Mag, 7mm Weatherby, 27 Boondoggle

These are the expected performance numbers from the 28" barrel. The 25" barrel will likely be 75-100 fps slower.

130gr: 3600 fps
140gr: 3500 fps
150gr: 3400 fps
170gr: 3200 fps

Here are the velocity results from today's testing. This was one shot at each powder charge while looking for max pressure.

Temp: 38°
Bullet: 145gr Hornady ELDx
OAL: 3.530"
Barrel: 28" Broughton 1-8.5"
Powder: Retumbo
Primer: Fed 215
Brass: ADG 338 RUM

90.0gr: 3489 fps
91.0gr: 3489 fps
92.0gr: 3541 fps
93.0gr: 3610 fps
94.0gr: 3626 fps

-------------------------------------------------------

Temp: 38°
Bullet: 145gr Hornady ELDx
OAL: 3.530"
Barrel: 28" Broughton 1-8.5"
Powder: IMR 7828
Primer: Fed 215
Brass: ADG 338 RUM

80.0gr: 3318 fps
81.0gr: 3337 fps
82.0gr: 3378 fps
83.0gr: 3411 fps
84.0gr: 3491 fps
85.0gr: 3484 fps
86.0gr: 3536 fps
87.0gr: 3551 fps
88.0gr: 3616 fps


The flat spots you see in the velocity in both the Retumbo (between 90 and 91gr) and IMR 7828 data (between 84 and 85gr) correspond with shots fired from a clean barrel. The barrel was cleaned after the 84.0gr and 88.0gr IMR 7828 charges and then the 90.0gr charge of Retumbo was fired.

I stopped shooting with both powders once I started to feel resistance on the primary extraction when opening the bolt. The 88.0gr charge of IMR 7828 would be a workable max charge. The 93.0gr charge of Retumbo would be a working max and I consider the 94.0gr charge of Retumbo too hot. The velocities I got are consistently 100 fps faster than what Quickload predicted, but the pressures seem to track pretty close. Based on this I feel pretty good about trusting the Quickload predictions.

From a function standpoint, everything worked great. All rounds were fed out of a 300 Win Mag AICS pattern magazine. The more I use the ARC Nucleus action, the more I like it. Feeding is incredibly smooth and ejection is perfect allowing me to either pull the case out of the action by hand or I can cycle the bolt fast and launch the brass 3 feet away.

 

[shinbone]

I like it!

The 270WSM is a great round. Since, more is better, the 270 Boondoggle should be awesome.

 

[jjmp]

Congrats!!! Always room for another 270 Cartridge looks very well thought out . Cheers!!!.

 

[MudRunner2005]

Better watch out... Hornady will try to steal that and call it the .270 PRC... And it will be the next ex-thing...Right in line behind the WSSM cartridges and the 6.8 SPC...

 

[yorke-1]

Better watch out... Hornady will try to steal that and call it the .270 PRC... And it will be the next ex-thing...Right in line behind the WSSM cartridges and the 6.8 SPC...

It's interesting that you give Hornady credit for the "next ex-thing" and then use Remington and Winchester designs as examples.

FWIW I did actually like my original design based off of the 375 Ruger case better than the final design I ended up with based on the 338 RUM. Using the 375 Ruger case also allows the 8x68s case to be used as an alternative. I wasn't originally chasing velocity with this project but since the case capacity is there now I may as well use it.

 

[MudRunner2005]

It's interesting that you give Hornady credit for the "next ex-thing" and then use Remington and Winchester designs as examples.

FWIW I did actually like my original design based off of the 375 Ruger case better than the final design I ended up with based on the 338 RUM. Using the 375 Ruger case also allows the 8x68s case to be used as an alternative. I wasn't originally chasing velocity with this project but since the case capacity is there now I may as well use it.

Yes, but they were still fails, regardless of who designed them. Hornady has never had any cartridges until recently. The 6.5CM (2007) was the first one they got behind exclusively, and now with the PRC line, they are entering the cartridge designing game. Personally, once the hype starts to die with the 6.5 PRC, I see it going the way of the Dodo bird, too, other than small niche groups of shooters.

Rich's 6.5 SS beats the PRC in every single way, unfortunately no major manufacturer has gotten behind him to start chambering rifles in it. If they did, it would destroy the PRC's sales. Everyone wants to chase horsepower, and the SS is 100-150 FPS faster.

As much time, work, effort, and money as Rich has put into his wildcats, I would love to see them hit the mainstream. It would change the game for factory rifles with real world functional cartridge design upgrades over the standard same-ole, same-ole everybody has been using for 100 years. Old school still works, but improved design works better, IMO.

 

[Alibiiv]

Yes, but they were still fails, regardless of who designed them. Hornady has never had any cartridges until recently. The 6.5CM (2007) was the first one they got behind exclusively, and now with the PRC line, they are entering the cartridge designing game. Personally, once the hype starts to die with the 6.5 PRC, I see it going the way of the Dodo bird, too, other than small niche groups of shooters.

Rich's 6.5 SS beats the PRC in every single way, unfortunately no major manufacturer has gotten behind him to start chambering rifles in it. If they did, it would destroy the PRC's sales. Everyone wants to chase horsepower, and the SS is 100-150 FPS faster.

As much time, work, effort, and money as Rich has put into his wildcats, I would love to see them hit the mainstream. It would change the game for factory rifles with real world functional cartridge design upgrades over the standard same-ole, same-ole everybody has been using for 100 years. Old school still works, but improved design works better, IMO.

"Ole school!!???? Ya just had to go there didn't you..

 

[MudRunner2005]

"Ole school!!???? Ya just had to go there didn't you..

It is what it is. Old tech still works fine...But nearly vertical walls and high shoulder angles are proven to be more efficient and better at handling chamber pressures than low-taper walls and low shoulder angles.

 

[Alibiiv]

It is what it is. Old tech still works fine...But nearly vertical walls and high shoulder angles are proven to be more efficient and better at handling chamber pressures than low-taper walls and low shoulder angles.

Ole school is up there with 6.5 Creed, and that's when the fight started!

 

[Alibiiv]

It is what it is. Old tech still works fine...But nearly vertical walls and high shoulder angles are proven to be more efficient and better at handling chamber pressures than low-taper walls and low shoulder angles.

Like the ole school Ackleys?

 

[cape cove]

@yorke-1
Good workl

 

[MudRunner2005]

Like the ole school Ackleys?

Yes, they are old school. But people seem to think the AI design features are something new. And in the SAAMI spec'd mainstream cartridge world, they kind of are.

By old school tech, I mean, look at the .30-06 Sprg. design... That's old school tech. Then look at the .28 Nosler...That's Ackley-style design, which was back in the 50's and 60's, but even then it was over a half century newer tech than the .30-06 Springfield was.

 

[therifleman556]

Better watch out... Hornady will try to steal that and call it the .270 PRC... And it will be the next ex-thing...Right in line behind the WSSM cartridges and the 6.8 SPC...

Are you just plain out to **** on and put down any cartridge that's not 7mm or designed by Rich? Looks like somebody thought it'd be fun to build their own rifle in something different for the fun of it. Where's the "hey good work" or " that looks interesting"? Seems like nothing but negativity out of you from the word go. Take a fun thread about something different and make it about how much you hate Hornady.

To the op; that looks like a heckuva fun round. Think you could hit 3800 with light monos?

 

[MudRunner2005]

Are you just plain out to ---- on and put down any cartridge that's not 7mm or designed by Rich? Looks like somebody thought it'd be fun to build their own rifle in something different for the fun of it. Where's the "hey good work" or " that looks interesting"? Seems like nothing but negativity out of you from the word go. Take a fun thread about something different and make it about how much you hate Hornady.

To the op; that looks like a heckuva fun round. Think you could hit 3800 with light monos?

It's called a joke, dude... Thought that was pretty apparent at this point...Guess not.

And no, I'm not out to crap on anything that's not 7mm or designed by Rich. I have lots of rifles chambered in many different calibers and chamberings. I actually have (at the moment) more .30 caliber rifles than I do 7mm's in my safe. None of which are Sherman cartridges.

And actually, I was complimenting him indirectly (some people understand subtlety)...By saying it was nice enough that Hornady might try to rip it off. You don't always have to bust out with the obvious "atta' boy" every time.