Sneak peak at the 27 Boondoggle

[yorketransport]

It's taken 15 months, a complete concept redesign, 4 different barrel makers and 2 different gunsmiths, but it's finally done (almost)! I ran out today after work just so I could fireform a piece of brass. I should get a chance to start load work in the next week or two depending on how busy I am at work.



I was initially going to use an X-Caliber 1-7" twist barrel but when that showed up the bore looked so rough that I just sent it back to them and got a refund. After that I picked up a sendero profile 1-7" twist McGowen barrel. When that showed up it looked great (like every other McGowen barrel I've had) but I decided that I wanted to go with a sporter contour instead, so I sold the sendero profile barrel. This time I called up K&P barrels and ordered up a 25" #5 contour 1-7" twist barrel which I had in my hands in less than 4 weeks! While waiting though, I traded my way into a 28" Broughton 1-8.5" heavy varmint barrel. I decided to just have both the 1-7" and the 8.5" twist barrels chambered up and have one hunting barrel and one target barrel made.

The original design for the 270 Boondoggle was to use the 375 Ruger case but when that reamer turned into a frag grenade while chambering a barrel, the project went a different direction. After that I was just going to go with the 27 Nosler but then decided that the 27/28 Nosler would be a bit more interesting and offer a bit of a performance bump. About that time I had a few issues with the smith who had been handling the build, so I decided it was time move on entirely. I worked with the guys at Hammer Bullets to get my project into the hands of a new smith, so now all that I needed to do was come up with a chambering for the gun. I didn't really love the idea of the 27/28 Nosler just because the brass options are a little limited and I just don't like Nosler brass. About this time I found out that ADG is making 338 RUM brass. I looked at some case dimensions and came up with an idea for the final version of my Boondoggle. What I ended up with is essentially a 27 Nosler reamer that's been pushed .130" deep so that the shoulder matches the position of the shoulder on the 338 RUM case. The shoulder diameter is slightly larger on the Nosler case and the shoulder angle is 35° instead of the 30° on the RUM. This means that standard 27 Nosler dies can be used and just held .130" off the shell holder.

Here's a 338 RUM case on the left and a formed 27 Boondoggle on the right.


Performance wise, here's a break down of what I'm look for from the 28" barrel, the 25" hunting barrel will come in 75-100 fps slower:
130gr: 3600 fps
140gr: 3500 fps
150gr: 3400 fps
170gr: 3200 fps

These are rough estimates just based on what I've seen from the 6.5 Badger (which is similar in capacity), 270 WSM and the 270 RUM. I think these are pretty conservative estimates but at the same time I don't really plan to just run this as hard as I can. I'm hoping that I'll have better results with the ADG brass than I've had with Nosler and Remington RUM bras in the past. The Nosler and Remington RUM brass has always been inconsistent and sloppy.

For comparison here a couple of other cases lined up. I couldn't find my 270 WSM or 270 Weatherby brass so I substituted 300 WSM and 7mm Weatherby cases which are the same except for neck diameter.
Left to right: 270 Win, 300 WSM, 7mm Rem Mag, 7mm Weatherby, 27 Boondoggle

[h20hunter]

Is that boondoggle or boondoogle?

[yorketransport]

Is that boondoggle or boondoogle?

I completely for got about that part of the whole story!

The smith sent me a picture of it when he finished up the barrels and that was the first thing I pointed out to him. He panicked because he knew that he was the second smith to make a significant mistake on this project. I thought it was pretty funny and almost had him just cross out the extra O and make it a G but decided that leaving it as "Boondoogle" summed up the whole project perfectly.

[jasnt]

Looking like 22-250 speeds. Awesome

[zwickeyman]

Flat shooter for sure.

500 fps faster than my 270 win 

[Dan-o]

Holy crap....................................

The ultimate Boondoogle!

[b23]

Yorke, what are you thinking for powder choice/s?  I'm guessing something at least as slow as Retumbo or probably slower maybe.  Have you by chance measured the case capacity of that beast, somewhere around 105-ish +/- ??

[Fl0und3rz]

How many barrels per round you expect to get out of it?

[Mtnwalker]

How many barrels per round you expect to get out of it?

 

[Alchase]

This is cool, thanks for taking us along on your adventure or “Boondoogle” LOL

It has been fun to follow!

[yorketransport]

Yorke, what are you thinking for powder choice/s?  I'm guessing something at least as slow as Retumbo or probably slower maybe.  Have you by chance measured the case capacity of that beast, somewhere around 105-ish +/- ??

Case capacity on my fired case is 110.6gr of water to the top of the neck. I was pretty happy with that since my estimate was 110gr. The test round that I fired was 75.0gr of Retumbo and a 145 ELDx. I'll probably start with H100 and Retumbo for the light weight bullets up to about 130gr. I think powders like Reloader 33 and slower will work best for the 170gr bullets. I used US869 in the 270 RUM with the 140gr bullets and it worked pretty well. I still have about 6# or US869 sitting around as well as about 14# of H50bmg that I'll try as well.

I took a lot of what Biggerhammer and I learned from working with the 6.5 Badger and tried to make some adjustments to make the Boondoggle a little more user friendly. The 6.5 Badger case wins in the case capacity department, but at the cost of powder selection. The 40° shoulder on the Badger and the small bore diameter caused some powder bridging issues with extruded powders. Going to a .270 and keeping a 35° shoulder angle helps solve a lot of those problems. Then I looked at what I learned by working with the 270 RUM and realized that there really wasn't a need for more than 110gr capacity and the shorter length of the 338 RUM case just works better on a gun that's going to be mag fed.

The big thing I wanted to do is follow my basic rule of being able to use off the shelf dies if I wanted to. I'm so sick of paying a couple hundred dollars and waiting 3-4 months for custom dies that I'll do anything I can to avoid it. To form the Boondoggle brass I size the 338 RUM case down using a 300 SAUM die then a 270 WSM die with out the expanders, both dies that I have sitting around. Then I anneal the cases and run them into a 27 Nosler die with the expander just enough to push the shoulder angle to 35° and get the necks right. Bullet seating, neck sizing and bumping the shoulder can all be done with the 27 Nosler die set.

I won't know whether or not to call this a success until I've had a little time to play with different powders and bullet combos, but I'm feeling pretty good about the chambering. If it works out, I'll order up an actual chamber reamer and headspace gauge instead of just using a 270 Nosler reamer run .130" deep. The rest of the project has been a spectacular failure though.

[b23]

The rest of the project has been a spectacular failure though.

Well, at least the failure was a spectacular one, and not just some limp boring run of the mill failure, so at least you got that going for you.  You know, one of those glass half full instead of half empty metaphor things.

[Fl0und3rz]

This is cool, thanks for taking us along on your adventure or “Boondoogle” LOL

It has been fun to follow!

Yeah, I am really just following along, but I wanted to tag with style.

[yorketransport]

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'll 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.

[Crunchy]

That is smoking fast.  Looks like you guessed right with the 145 ELDx load right off the back.