Anyone try heavy 308s in a 5-R barrel?

[mleeber]

I have a pet load for 308 which uses a 210gr SMK (don't need to argue about the 210 being too heavy for 308, it works well and the proof is in the groups I am getting). I am getting 1/2 MOA or better out of an 18" barrel in an LR-308. I am looking to add a Remington 700 to the collection and trying to decide between a 1 in 10 twist run of the mill Remy barrel (in an SPS Tactical AAC) and the 5-R 1 in 11.25. My concern is that the 210gr bullet will not stabilize in 11.25. Anyone have any experience with heavy bullets in a Remy 5-R barrel?

Thanks!

 

[stanley52]

Go to.... JBM - Calculations - Stability

Just punch in your data and go. Make sure you click on the explanation of terms to know what their system of rating stability means. As a rule of thumb, match shooters choose the slowest twist that will stabilize their bullet, if that helps.

 

[MudRunner2005]

I have a 5R .308 Win and I have a pet load using 210 Berger VLD's. it shoots 1-hole cloverleafs.

Left: Nosler 168 Custom Comp seated to SAAMI spec 2.810"
Right: Berger 210 VLD load

It loves the 168 load seated to SAAMI spec...That allowed me to shoot a 1.286" 24-shot group.

 

[mleeber]

Thanks!!!! Nice little tool. I get a value of 1.290. My understanding is that the 5-R barrel is a hammer forged 5-grove polygonal rifled barrel, I wonder if this changes the calculation?

 

[mleeber]

MudRunner, that is exactly what I was looking for! What is the BC on the Berger 210? The SMK is .645 at 1800 FPS and above and it is 1.483 long. I suspect that the Berger is similar. Thanks!

P.s. I am limited in the DPMS on oal by the magazine but with the long Remy chambers my rounds should look much more like yours.

 

[stanley52]

Thanks!!!! Nice little tool. I get a value of 1.290. My understanding is that the 5-R barrel is a hammer forged 5-grove polygonal rifled barrel, I wonder if this changes the calculation?

It shouldn't change it, at least on a registerable level. The only significant shifts you might see would be because of barometric pressure.

 

[mleeber]

I ran the same data for a 10 twist and got 1.63. Very surprised that 1.25 makes that big a difference.

 

[MudRunner2005]

MudRunner, that is exactly what I was looking for! What is the BC on the Berger 210? The SMK is .645 at 1800 FPS and above and it is 1.483 long. I suspect that the Berger is similar. Thanks!

P.s. I am limited in the DPMS on oal by the magazine but with the long Remy chambers my rounds should look much more like yours.

The Berger 210 VLD G1 BC is 0.631, and the G7 BC is 0.323

 

[Canadian Bushman]

Mudrunner, what kind of speed are you getting out of that berger?

 

[MudRunner2005]

Mind you, my 5R .308 is one of the not-as-common 24" models (which I prefer) for longer range stability. I am getting just at 2400 fps MV.

 

[mleeber]

hmmmm....I am only getting 2054 with an 18" barrel but I am using a very fast powder (for 308). I am trying to figure out if I want to get a 24" gun and thread the barrel or a 20" with the barrel already threaded.

 

[Canadian Bushman]

I am getting just at 2400 fps MV.

That sounds like a nice 308 round

 

[MudRunner2005]

That sounds like a nice 308 round

Yep, plus that load is stacking them in nearly 1 hole @ 100 yards, if the nut behind the trigger (me) does his part, of course.

 

[mleeber]

What are you using for a powder?