I finally got around to loading up some 400gr NF Cup Points for the 450/400.

Starting load was 66gr of RL 15, and that one turned out to be a little too hot (guess I've got a "fast" batch of RL 15.)

What was impressive though was the velocity consistency.
R1 = 2125
L1 = 2127
R2 = 2125
L2 = 2127

Yes, the velocities were exactly the same per barrel/per shot... Oehler 35P.

These were laoded with the foam filler I posted last week.



I'll start working back from 66gr and post the results when the bullets are regulating.

FWIW - the NF cup points grouped about 4" higher at 50yds.

Chris,I thought you only used H4831 to keep it simple.Have a change of heart?Also,do you still carry those snap caps for a 450/400?If so,how much are they?

Your lot must really be fast.

I load 72gr of RL 15 in my 450/400 3 1/4".

I wonder what the velocity would be with 400 gr Woodleigh's with 66 gr in your gun...

New Guy,

Your backer rod may be giving you higher pressures in the 450-400. I have used backer rod for years and I do not use it in bottle necked cases because pressures seem higher. I tried it in my 450-400 and got sticky cases with normal loads of RL 15. You may however have hit the sweet spot.

Sam

quote:

Originally posted by zambezi:
Chris,I thought you only used H4831 to keep it simple.Have a change of heart?Also,do you still carry those snap caps for a 450/400?If so,how much are they?

That's true. I have always avoided fillers, but as I recently noted, I'm getting more and more questions about them and thought I should get some practical experience.

The consistency is impressive, but I did not notice a measurable amount of decreased recoil.

Yes, still have a few snap caps but not many. They are $40/pair.

new_guy,

Please explain, for one who has not used fillers, how you use this product with your 450-400.

Thanks

Chris, yes per Ken Owen RL 15 = less pressure = less recoil. This has been my experience as well.

Tony, FYI, my .450/.400 3 1/4" likes 70 gr. RL 15.

Sam, agreed, backer rod for the straight cases. Dacron filler for the bottle necked. Consulted with "bike rider" (re: my .360 No.2) today and he agreed.

RL-15 results in less recoil because cartridges typically use less of it than most other powders. Nothing to do with pressure.

quote:

Originally posted by new_guy:
I finally got around to loading up some 400gr NF Cup Points for the 450/400.

Starting load was 66gr of RL 15, and that one turned out to be a little too hot (guess I've got a "fast" batch of RL 15.)

What was impressive though was the velocity consistency.
R1 = 2125
L1 = 2127
R2 = 2125
L2 = 2127

Yes, the velocities were exactly the same per barrel/per shot... Oehler 35P.

These were laoded with the foam filler I posted last week.



I'll start working back from 66gr and post the results when the bullets are regulating.

FWIW - the NF cup points grouped about 4" higher at 50yds.

My guess is that the pressure is quite high at those velocities out of 24" barrels.

quote:

Originally posted by Will:
My guess is that the pressure is quite high at those velocities out of 24" barrels.

These barrels are 26".

Factory Hornady usually runs 2080-2100 in them.

Either way, this load was crossing a bit at 50 and is faster than I need to shoot well.

Thanks for the info. Pressure is a weird thing. When I think I know how to predict it the data doesn't match.

Whether one really cares if the pressure is low or high I guess I don't know. I always try to get nominal velocity at a pressure as low possible. Chronos are probably just not sufficient. One of the powders that Mike used resulted in decent velocity and low pressure. Can pass that along to you if you want.

Beat you to it

Referring to Gramme Wrights 3 rd edition on DRs
and I don't remember the page#... The 450/400 is the largest double rifle case where fillers are not needed with RL 15. My K-gun shoots 70gr. and any of the 400gr North Forks just fine
at a speed from 2125 to 2140 consistently from both barrels over an Oheler 35P. (24 inch tubes)
I tried fillers once, couldn't measure the pressure but the cases stuck in the chambers then finally fell out after cooling off about 2 minutes. Not good on a Buffalo hunt. I quit
playing with fillers in the 450/400 3in. Too much success without and good speed and groups to boot. Also less recoil than 81 gr H4831SC.
I got 2 pair of Chris' snap caps and they are great.
Good shooting......

Tetonka
DRSS

quote:

Originally posted by tetonka:
I tried fillers once, couldn't measure the pressure but the cases stuck in the chambers then finally fell out after cooling off about 2 minutes. Tetonka DRSS

Did you note the velocity on those two rounds?

A lot has been said here about increasing pressure or high pressure, but I think it's important for readers to understand that pressures don't just go up without increasing velocity.

As noted in this load I tried first 66gr RL-15. Velocity was over what I was expecting. That tells me that the pressure was also higher than what I wanted.

I don't have a means of measuring pressure directly, but I know that (with given components) it takes more pressure to equal more velocity.

That's why we should all use chronographs. If a particular recipe is giving you significantly higher velocity than you expected - despite the fact that you're using less powder than the publishied data indicates, then your load is over pressure.

quote:

That's why we should all use chronographs. If a particular recipe is giving you significantly higher velocity than you expected - despite the fact that you're using less powder than the publishied data indicates, then your load is over pressure.

Bingo.

There are two pressures, the peak pressure and then the decreasing pressure as the bullet goes down the barrel. Even if a peak pressure is lower, a higher "Average" pressure must exist in the barrels to get the higher velocity at the lower peak pressure.

Whether the higher average pressure resulting from slow burning powders is a good thing in thin DR barrels or not is open to discussion.

And wads increase peak pressures. It probably doesn't matter when shooting the tank versions of DR's. Whether the increased powder with no wad kicks more also probably doesn't matter in a 11 or 12 pound 470.

But in a little, tiny 7 lb. 450 NE DR like mine, both high pressure and greater recoil are big deals and to be avoided.

You should just tell the flock the powder that doesn't need a wad and apparently gives low pressure.

7 lb 450 X 3 1/4? OUCH!

quote:

Originally posted by Will:

quote:

That's why we should all use chronographs. If a particular recipe is giving you significantly higher velocity than you expected - despite the fact that you're using less powder than the publishied data indicates, then your load is over pressure.

Bingo.

There are two pressures, the peak pressure and then the decreasing pressure as the bullet goes down the barrel. Even if a peak pressure is lower, a higher "Average" pressure must exist in the barrels to get the higher velocity at the lower peak pressure.

Whether the higher average pressure resulting from slow burning powders is a good thing in thin DR barrels or not is open to discussion.

And wads increase peak pressures. It probably doesn't matter when shooting the tank versions of DR's. Whether the increased powder with no wad kicks more also probably doesn't matter in a 11 or 12 pound 470.

But in a little, tiny 7 lb. 450 NE DR like mine, both high pressure and greater recoil are big deals and to be avoided.

You should just tell the flock the powder that doesn't need a wad and apparently gives low pressure.

Sorry Chris,

no chronograph on the rainy day I tried the filler so no velocity results. Just stuck cases and hard opening. Only tried 2 rounds and promptly gave up on that idea. Possibly could have dropped the load and kept working but went back to the shop and re-read Wright's
3 rd edition on RL 15 and decided to go with no filler. Results turned out good. I still have a good load for H4831SC, more powder than
RL 15 and a little less velocity (about 100fps)
average. More felt recoil with the 4831 also.
With regard to velocity 75 Gr RL#15 in good wifes 450/400 3 in Ruger # 1 produces 2500fps with North Fork 360gr.SP. Awsome power, and the Ruger handles it fine. But not for doubles.

Could have been the type of filler I was using.
Got the idea from old Sharps buffalo BP cartridge reloading info. with substitutes for BP in old Sharps cartridges.
Do Not Try Yellow Corn Meal as a filler in large case African type big bore cases.

Live & Learn, Always use Chronograph even on
rainy days when developing loads.

Good shooting

Tetonka
DRSS