Sneak peak at the 27 Boondoggle

[b23]

Yorke, with that round of testing, how close were you seating your bullets to touching the lands?

[yorketransport]

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

I'm getting pretty good a making up random load data. I tried using Retumbo with 140gr bullets in the 270 RUM a few years ago so I had a pretty good idea where to start. I had to start a little lower with the IMR 7828 since I've never played with it in an over bore 270 before.

Yorke, with that round of testing, how close were you seating your bullets to touching the lands?

The Hornadys were .020" off the lands. Both chambers were cut so that I could seat the 168 Hammer Hunter .020" off the lands with an OAL of 3.720" which puts the ELDx at 3.530". I'll leave the throat on the 25" 1-7" twist barrel this way since it's intended to be a hunting barrel. I'll probably extend the throat on the 28" barrel so that I can seat the 170gr EOL .020" off the lands at 3.720" OAL since that's about the max that feeds through the Wyatt's mag that I've got.

[yorketransport]

Here's an update on the 27 Boondoggle. I had it out last Saturday to start some accuracy testing and ended up with some less than spectacular results with both barrels; in the realm of 2 MOA at 200 yards. Everything about that seemed wrong! At that point, there were only 30 shots fired through the 28" barrel and 10 through the 25" barrel. I took it home, tore it all apart to check everything, clean the  barrels and trouble shoot. With no obvious issues, I threw it all back together and loaded up 3 different loads with 3 different bullets to see what I would come up with and headed back out on Sunday.

This time I started the day by shooting the well proven 6.5 Badger barrel to make sure the action/stock/optic were all still behaving as normal and was rewarded with a .5 MOA group; exactly what I expect from that combo. I screwed the 28" 27 Boondoggle barrel back on there and shot these groups at 150 yards. All loads used 92.0gr Retumbo.

140 Ballistic Tip


140 Sierra TGK


145 ELDx


For scale, the dot is 1.25". So now I have one group that's just bad, one stringing vertically and one stringing horizontally. This rules out an issue with the optic or bedding and points to loads which are completely out of tune. I've never had a barrel shoot this poorly with any combination of powder or bullets, let alone 3 different bullets! These groups were shot without the Magneto on there so I don't have velocities for the groups. Now there's 45 rounds through this barrel.

After a week of brainstorming and trying to diagnose the issue it's decided that this barrel either needs a long break in period or it's just very particular about what loads it will shoot well. I took it out again to day, this time doing a conventional ladder test at 380 yards to see what's going on. This time I had the Magneto mounted on there to get velocities while shooting. The wind was pretty erratic, so I was focused more on my vertical rather than chasing wind calls. The numbers next to each hole are the velocities for that shot. Both bullets were shot with powder charges starting at 90.0gr Retumbo and working up in .5gr increments. I got up to 93.0gr with the ELDx and up to 93.5gr with the 140 TGK. The black diamond is roughly 5" from point to point.



Now I'm getting somewhere and I'm seeing an explanation for the erratic groups before. As the barrel is breaking in, I've gained 100 fps! It looks like the velocity is stabilizing now and you can see that 93.0gr of Retumbo gave 3701 fps with the ELDx and 3703 fps with the TGK. The ELDx hit a flat spot in velocity at around 3550 fps with one shot dropping low, but that was caused by a bent tip (I dropped that round and expected a flyer). The 140 TGK shows a good node at the top end around 3700 fps with only 1.5" of vertical at 380 yards between 92.5gr and 93.5gr. That's not bad at all! That load is at the top end of what I'd shoot, but bolt lift is still reasonable.

Next weekend I'll head out with the ELDx loaded up at about 90.5gr and I'll try the 140 TGK again at 92.5gr.

[Jpmiller]

Cool! This whole thing fascinates me

[Crunchy]

Yorke,
How do you like your magneto speed?  I am trying to decide between it, and a labradar.

[yorketransport]

Yorke,
How do you like your magneto speed?  I am trying to decide between it, and a labradar.

If you can drop the extra money and you shoot alone, get the labradar. The magneto does a great job of getting accurate velocities and it's easy to setup and use if you're shooting around a bunch of other people. The labradar has the advantage of not being strapped to the barrel though. I wouldn't sell my magneto to buy the labradar, but if the labradar had been out when I bought the magneto I would have bought it instead.

[Crunchy]

yeah, sometimes the rifle range I shoot at gets crowded.  So the magneto speed might be the better option.

[CAMPMEAT]

Let's see the entire gun.........

[Magnum_Willys]

The magneto speed is like a tuning weight. It affects impact points. One variable I don’t need. Labrador for me. Imo

[yorketransport]

The magneto speed is like a tuning weight. It affects impact points. One variable I don’t need. Labrador for me. Imo

I rarely see a change in group size, just point of impact. I never zero with the Magneto mounted on the barrel though and I always shoot groups with it off.

Let's see the entire gun.........

It's nothing fancy, still a bit of an unfinished project. I haven't found a stock that I really like yet so it's still sitting in one of the Stocky's composite stocks. It's not a bad stock, the comb is just too low. It doesn't help that the scope rail on the Nucleus action is so tall. Even with low rings I needed to raise my cheek up almost 1/2" to get a good cheek weld.




The more I shoot the Nucleus action though the more I like it; it's breaking in really well and feeds perfectly from the magazine. I don't like the Calvin Elite trigger that's on there but I don't dislike it enough to spend $150-200 on a different trigger. I have a Jewel HVR trigger that I used on there initially but I didn't like having the bottom safety on this gun and the 6oz trigger wasn't a good fit on this rifle.

[yorketransport]

Here's the Boondoggle update: I give up.

After testing 5 bullets and 3 powders in two different barrels with 2 different scopes, I can't get it to consistently group under .75 MOA. I'm talking with the smith who did the barrel work and I'm probably going to cut 1/2" off the shanks and on both barrels and just sell them for somebody else to chamber for the 27 Nosler. I won't waste my time with a gun that shoots this poorly. The odds of having 2 bad barrels is pretty unlikely, so it looks like this is just bad smith work.

The sad part is that both barrels should be shooting really well based on everything I've seen. This was from my seating depth tests with Reloader 33 and the 170gr Berger EOL in the 25" barrel.

The groups were all 3 MOA at 270 yards though. Too bad, because 3200 fps with a 170gr bullet from a 25" barrel would have been pretty nice!

[jasnt]

That’s bummer. Up hill battle since day one       So what’s to become of the nucleus

[yorketransport]

I'll just throw the 6.5 Badger barrel back on there for now. I have a set of dies for the Sherman version of the 300 PRC improved on the way (someday...) so I'll stumble onto a 30 caliber blank at some point and go that route. Then I might just copy you and order up a Savage prefit in 338 RCM and chamber up another 338/375 Ruger barrel.

I told the smith that I'd give it one more trip out before walking away from it. I'm going to tear it all apart and re-bed the stock just to rule out any thing like that too.

[jasnt]

I’ve been thinking about ordering another barrel too. One much lighter for hunting with

[Jason]

I’ve been thinking about ordering another barrel too. One much lighter for hunting with

Group buy? I’m probably not going to use the X-Caliber 338 contoured blank that I just bought.