338/375 ruger finished

[jasent]

I ran it up to 3030fps but it shot better at 2990. I haven't found any re16 in my area but I'll keep looking. At 77.5 gr of h4350 I had a stiff bolt lift. I've only gotten 78 rounds down the tube so it may speed up a bit. But right now I'm happy with the speed.

 

[WildRose]

I ran it up to 3030fps but it shot better at 2990. I haven't found any re16 in my area but I'll keep looking. At 77.5 gr of h4350 I had a stiff bolt lift. I've only gotten 78 rounds down the tube so it may speed up a bit. But right now I'm happy with the speed.

You might find a happy spot with RL17 or 19. That's what I'll be running in the .375Ruger and maybe the 6.5Lrm this year as well.

 

[LeddSlinger]

You might find a happy spot with RL17 or 19. That's what I'll be running in the .375Ruger and maybe the 6.5Lrm this year as well.

RL17 gives really good speeds in the 338-375 as well. I have reservations about using that powder because it is a barrel burning son of a gun (burns at an extremely high temp) and it's pretty sensitive to temp changes. Great powder for hunting rifles if you develop your load in hunting temps and don't shoot the rifle a ton.

RL19 is another good one for speed. Very temp sensitive tho. RL22 is also very temp sensitive. RL17 will do everything 19 and 22 can do combined. After that a person can just jump to RL26 for rifles that like slower powders.

RL16 has an amazing resistance to temperature changes.

 

[jasent]

You might find a happy spot with RL17 or 19. That's what I'll be running in the .375Ruger and maybe the 6.5Lrm this year as well.

i have a bunch of re17 but I don't like the temp sensitivity it has. I shoot from sub freezing to 100f. I've seen huge swings with re17

 

[yorke-1]

You might find a happy spot with RL17 or 19. That's what I'll be running in the .375Ruger and maybe the 6.5Lrm this year as well.

I tried Reloader 17 about 6 years ago with mixed results. I got some spectacular velocities from an 18" barrel but pressures went from .002" case head expansion and easy extraction to .005" expansion and a stiff bolt in less than .5 grain increase.

Hodgdon H100-v works really well for giving extra velocity at more predictable pressures. It just hasn't been as accurate in my guns.

 

[WildRose]

RL17 gives really good speeds in the 338-375 as well. I have reservations about using that powder because it is a barrel burning son of a gun (burns at an extremely high temp) and it's pretty sensitive to temp changes. Great powder for hunting rifles if you develop your load in hunting temps and don't shoot the rifle a ton.

RL19 is another good one for speed. Very temp sensitive tho. RL22 is also very temp sensitive. RL17 will do everything 19 and 22 can do combined. After that a person can just jump to RL26 for rifles that like slower powders.

RL16 has an amazing resistance to temperature changes.

With most of the powder being burnt in that fat case and very little flame going up the pipe I don't worry about it. I didn't buy any of these as high volume shooters so they will probably all outlive my shooting years considerably and still be shooting great when Mario's kids run off with them.

 

[WildRose]

I tried Reloader 17 about 6 years ago with mixed results. I got some spectacular velocities from an 18" barrel but pressures went from .002" case head expansion and easy extraction to .005" expansion and a stiff bolt in less than .5 grain increase.

Hodgdon H100-v works really well for giving extra velocity at more predictable pressures. It just hasn't been as accurate in my guns.

When you start approaching max loads those pressure increases come on in very tiny increments in a hurry at least in my experience. Less of course with slower powders but for some reason I don't understand my standard "go to" slower powders just don't want to work with this case at least according to QL and I'm not real adventurous when it comes to experimenting any more with no solid data to work from.

 

[Wild Monkey]

.

 

[Wild Monkey]

.

 

[jasent]

338rcm is just a shortened 338/375 ruger. The shoulders are identical I use 338rcm dies to seat and size the neck. Bump the shoulder with the 375 die w/expander ball removed.
Reamer fit perfectly in the rcm chamber and I reamed it .480" deeper. It's a simple neck down and load. No fire forming needed with Hornady 375 ruger brass.

 

[LeddSlinger]

My chamber is just a 375 Ruger case necked down to 338. No other modifications to the design.

Redding makes actual 338-375 Ruger dies (which is what I have), or you can have Whidden make you a set from your reamer print or fired cases. Whidden wasn't making dies back when I built my 338-375R (at least not to my knowledge) or I would have went that route. I use Whidden FL bushing sizer dies for some of my other chamberings and they are definitely much higher quality.

Nowadays for seating dies on custom rifles, I buy Wilson micrometer arbor die blanks and have my seating dies custom made with my chamber reamer so they are an exact match. But Whidden seating dies are also very nice.

 

[WildRose]

My chamber is just a 375 Ruger case necked down to 338. No other modifications to the design.

Redding makes actual 338-375 Ruger dies (which is what I have), or you can have Whidden make you a set from your reamer print or fired cases. Whidden wasn't making dies back when I built my 338-375R (at least not to my knowledge) or I would have went that route. I use Whidden FL bushing sizer dies for some of my other chamberings and they are definitely much higher quality.

Nowadays for seating dies on custom rifles, I buy Wilson micrometer arbor die blanks and have my seating dies customach made with my chamber reamer so they are an exact match. But Whidden seating dies are also very nice.

DD do you run into any issues necking down in one step from .375 to .338?

 

[jasent]

No troubles necking down in one step.

 

[LeddSlinger]

DD do you run into any issues necking down in one step from .375 to .338?

Not at all. It's about as far as a person wants to go in one step, but works fine. Never crushed a shoulder or ruined a case otherwise. Just one pass with 375 Ruger brass in my 338-375R FL sizer die and I'm ready to load.