6 BR/Dasher vs 30 BR

[Keechi Kid]

So I have had a slow developing plan to build a lightweight, short barreled bolt action rifle for suppressed use at relatively short ranges. For most purposes, would be shots under 200 yards. In the beginning, the rifle in mind would be built off some form of mini-mauser such as the small zastava or cz 527 in something like 300 blackout and building it around using the Barnes 110 tac-tx bullet. I have found that bullet to perform well for me on quite a few deer and hogs over the years.

As this project continued to evolve in my mind and I continued to look at donor action options and the best way to get to my goal, a rifle as short as possible that is capable of quick kills on small-large game at named distance, what I was planning continued to change. The latest iteration in my mind was building on a stainless Kimber 84m action a 30 BR set up around the Barnes bullet.

However, my own personal experiences with 6.5-.308 Hornady ELD-M bullets and seeing some of the threads here about even smaller bore sizes performance with match bullets has me asking myself should I be looking at something even more different. So here is my question.

Building off a Kimber 84m, which has a number of characteristics I desire, with the goal of a barrel no longer than 16" and intended to be used with a suppressor (probably a Scythe TI) which caliber should I be looking at? A 6 BR/Dasher utilizing 108 gr ELD-M or the 30 BR using the Barnes 110 TAC-TX? I have thought larger bore size would have an advantage due to my goal of a shorter barrel, but now I'm less certain.

Curious what thoughts people here are willing to share.

 

[TaperPin]

I didn’t think I’d ever hear 30br mentioned. Lol

I have a 6br so I’ll probably get a 7br and 30br when good used barrels come up. The ppc, Arc, Grendel, or BR cases all fit nicely in little actions - hard to go wrong.

 

[Keechi Kid]

Well, goal is a case for .473 bolt face with a smaller case capacity. That’s what led me to the BR form factor.

 

[TaperPin]

Well, goal is a case for .473 bolt face with a smaller case capacity. That’s what led me to the BR form factor.

I’m looking forward to a 30br since it is something different.

You will hear about BR cases not feeding well in all actions, and it is a real thing, especially if you have a long bullet sticking out a long ways - with a single feed magazine it’s easier, but it’s common to have magazines modified with a spacer and/or work on the mag lips to help it into the chamber a bit.

This may or may not apply to your rifle, but Sako style extractors with a .473 bolt face can work on the PPC/Arc/Grendel case - I believe Borden rifle actions use that combination as standard practice.

 

[wind gypsy]

6 BR would be pretty awesome for your purpose. Loaded with 95 gr TMK if you can find them to get a little more velocity over a 108.

No idea what feeding in a kimber looks like.

 

[Keechi Kid]

I am aware feeding could be an issue and wouldn’t trust just any smith with it. However, I have a lot of confidence in who I have discussed this project with being able to sort it out. I am really curious if anyone out there has insight into how complete powder burn will be with these shorter barrels and smaller bores and if velocity is going to be sufficient

 

[Keechi Kid]

So I have been playing around a reloading program to estimate some velocities. The 6 dasher seems to win for efficiency and burning powder in a 16” barrel. With 31.5 grains of varget it burns over 99% of powder and achieves 2500 fps with a 108 grain ELD-M.

However, I have concerns about bullet performance at that velocity. I’m sure it will still be opening up well out to 200, but that puts me below 2200 fps before 200.

The 30 BR pushing the Barnes tac-tx is right around 2600 with 16” barrel and will be above 2500 at 14” of barrel if I go sbr, which I am really tempted to do since I want this short. Would love 20” total with suppressor. I know those velocities have me well without the right velocity windows for the 110 Barnes.

Anyone have any thoughts given these numbers?