Short Dasher help...?

[wilkup]

I'm in the final planning stages of a lightweight hunting rifle and would appreciate input from those with experience loading these shorties with bullets like the 80gr ELD-VT, 95gr Sierra TMK, 110gr Hornady Atip Match...
Build Concept:
Modified Howa Mini Action
- 1:7 twist - Preferred Sendero w/helical fluting - TBD on 16'' or 18''
- Dedicated direct thread suppressor - CAT WB Ti or OCL Hydrogen S (w/16" barrel)
- Stocky's VGM Mini carbon stock
- Jard Trigger - 6oz
- Use - PNW mule deer, bear, and predators
Primary Constraint:
My modified magazine still limits me to 2.45" COAL, so I'm stuck using shorter/lighter bullets not the popular 6mm HEAVIES.
Debating:
1. 16" vs 18" Barrel
I've spent several hours mapping the differences using Gordon's Reloading software at this point but what I'm seeing on there is different from what I'm reading/hearing guys tell me their real-world experiences have been. For those with experience shooting short Dashers or GTs:
- How much velocity is actually lost moving down from 18" to 16"?
- Was the loss noticeable in terms of wind drift, terminal performance, or effective hunting range?
- Was the longer barrel worth the performance increase?
My goal is a compact, 8lbs RTH (Scoped, loaded, suppressed) mountain rifle, but I'm willing to add 2" if the gain provided is meaningful.
2. 6 Dasher vs 6 GT
From my modeling using Gordon's Reloading software , the Dasher appears to produce nearly the same (within 10fps) velocity with:
- less powder
- lower gas volume
- better efficiency in short barrels
For those with experience loading both:
- Is there a practical advantage to the 6 GT when limited to 2.45" COAL?
- Here's what I've learned about the 6 Dasher performance on GRT:
- 35gr of Varget pushes the 80gr Hornady ELD-VT --> 3,081fps w/18'' barrel; 2,986fps w/16'' barrel
- 32.1gr of H4895 pushes the 95gr Sierra TMK --> 2,911fps w/18'' barrel; 2,830fps w/16'' barrel
- 33gr of Varget pushes the 110gr Hornady Atip Match --> 2,735fps w/18'' barrel; 2,656fps w/16'' barrel

Is there another bullet out there that better fits within my build concept that I've failed to consider?
Based on your experience, is there a significant advantage utilizing the longer barrel for a build like this?
Thanks in advance.

 

[43.6N]

Can’t speak for ladasha, but my GT with a saami throat, really shines with 2.6”+ bullets. Unless you spec your barrel to have a very short throat I have a feeling you would be jumping quite far with your magazine OAL limitation.

And with an 18” barrel: 107’s are at 2800 with 33gr Varget.
116’s did really well at 2730fps with 32.5-33gr Varget.

As far as your last question about other cartridges:
Why not look at 6ARC? It seems taylor-made for the action, OAL length restrictions, velocity, overall rifle weight, and exact bullets you are wanting to shoot.

 

[wilkup]

Can’t speak for ladasha, but my GT with a saami throat, really shines with 2.6”+ bullets. Unless you spec your barrel to have a very short throat I have a feeling you would be jumping quite far with your magazine OAL limitation.

And with an 18” barrel: 107’s are at 2800 with 33gr Varget.
116’s did really well at 2730fps with 32.5-33gr Varget.

As far as your last question about other cartridges:
Why not look at 6ARC? It seems taylor-made for the action, OAL length restrictions, velocity, overall rifle weight, and exact bullets you are wanting to shoot.

My rifle started life as an ARC and has experienced a couple changes in the past year while I tinker. I’m in the process of designing a dwarf version of the bottom metal similar to Unknown Munitions along with a CF detachable mag that will accommodate and centerfeed cartridges of at least 2.5” in the Mini with the mods I’ve done. Changing to the .473 boltface has been an awesome upgrade for me. I really love these little actions and once I get the new mag system sorted it’s going to be sitting in a class of its own.

 

[HandgunHTR]

Just one item about your potential build. A Sendero profile, even fluted is going to be heavy. With the stock you are considering, it is going to be very barrel heavy in regards to overall balance.

If you are truly wanting lightweight, I would recommend going with taperless .750, fluted, at the most.

 

[Treelineasassin]

There is no point in shoehorning the gt case into a 2.45 action. The gt is near 0.200 longer than a dasher. In a short 104 freebore dasher, coal touching lands is around 2.47-2.49 with heavies already, def don't want a longer case.

I've shot equal length gt VS dasher, not coal limited, but the gt holds 4ish gr more powder, it's faster at equal psi by prop 60-90fps depending on length. Sweet thing about the gt, you can run a slower burn powder like H4350.

 

[wilkup]

There is no point in shoehorning the gt case into a 2.45 action. The gt is near 0.200 longer than a dasher. In a short 104 freebore dasher, coal touching lands is around 2.47-2.49 with heavies already, def don't want a longer case.

I've shot equal length gt VS dasher, not coal limited, but the gt holds 4ish gr more powder, it's faster at equal psi by prop 60-90fps depending on length. Sweet thing about the gt, you can run a slower burn powder like H4350.

Based on all the scenarios I’ve run in GRT, I’ve come to the same conclusion. I think this will be the perfect dedicated Dasher rifle when I finish up with it.

 

[wilkup]

Just one item about your potential build. A Sendero profile, even fluted is going to be heavy. With the stock you are considering, it is going to be very barrel heavy in regards to overall balance.

If you are truly wanting lightweight, I would recommend going with taperless .750, fluted, at the most.

Taperless is a good call. Thanks
Because I have a suppressor going on it, I would think the Taperless .810 might be a better option for the bigger shoulder even though it’s gonna be a bit more weight.
The last Stocky’s CF I ordered I removed all the “fill” and sprayed it full of a much softer pliable closed cell, expanding foam and it feels a lot more solid. Also added a 1” Decelerator recoil pad for a little more comfortable LOP. If the weight is off I will add a bit of devcon epoxy at the butt end to balance it out.

 

[HandgunHTR]

Taperless is a good call. Thanks
Because I have a suppressor going on it, I would think the Taperless .810 might be a better option for the bigger shoulder even though it’s gonna be a bit more weight.
The last Stocky’s CF I ordered I removed all the “fill” and sprayed it full of a much softer pliable closed cell, expanding foam and it feels a lot more solid. Also added a 1” Decelerator recoil pad for a little more comfortable LOP. If the weight is off I will add a bit of devcon epoxy at the butt end to balance it out.

.750 gives you more than enough shoulder for a suppressor. Heck, I have a couple of .660” barrels that are directly threaded 5/8-24 and have never had a problem putting my DT suppressors on them.