This has been discussed many a time, and probably I'd find the answer if I were to take the trouble of using the "search" function - but I'll post instead.

When applying the "75% rule" to load for lighter bullets, what kind of velocities have you achieved?
I'd like to know the caliber you load for; the velocity with the heavier bullet; and the velocity with the lighter bullet.

- Lars

For my 450/400 3 inch I normally load 400 grain bullets over 63 grains of RL-15 plus either a Dacron Filler or foam plug. I can also use 300 grain Hawk bullets over the same powder charge. They shoot to the same POI as the 400 grains bullets. This method was discovered by 450#2 NE of this forum.

I don't know why, I just know it works in my double rifle!

In my 450 No2, using the 75% rule with 350gr bullets, and in my 450/400 3 1/4" using 300gr bullets, velocities are @2330fps to 2350fps.

Because the bullet is lighter than the full weight bullet recoil is reduced.

In you particular gun you might have to go up or down a grain or two of powder, but usually you make no changes from your full power load.

What calibre are you loading for?

Not loading for any calibre yet!
Pondering over the classic (?) dilemma of 9,3x74R v. .450/400 3".
It occurs to me that with 300grs bullets the .450/400 would be awfully close to the 9,3mm using 286grs bullets.
Living in Europe I have excellent access to the 9,3 ammo; and I'm having a hard time finding any real arguments in favor of the .450/400 - other than wanting one. And I'm particularly recoil shy, too.

quote:

Originally posted by N E 450 No2:
In my 450 No2, using the 75% rule with 350gr bullets, and in my 450/400 3 1/4" using 300gr bullets, velocities are @2330fps to 2350fps.

So about 200fps more than with the heavier bullets, right?
Rusty, how about you? Have you chronoed the loads, or are you just happy achieving the same point of impact? (Which, of course, is what counts. The velocity in such a case is more of academic interest.)

quote:

Because the bullet is lighter than the full weight bullet recoil is reduced.

Thanks - this was also part of the response I was after, but forgot to specifically ask.
Rusty? Any views on this one? I know you love your .450/400 so I'm particularly keen on your findings, too!

Thanks guys!

- Lars

The best choice is to get one of each.

I have a 9,3x74R double rifle amd I love it.

It is a GREAT hunting rifle.

I have taken a lot of game with it including cape buff and elephant.

I also have talken a lot of game with my 450/400.
I use it for deer, wild pigs, black bear, caribou, used it on a brown bear hunt but did not shoot one, as well as some Zimbabwe Plains game, a cape buff lion and bull elephant.

Both are excellent calibres.

They make a great pair.

quote:

Originally posted by N E 450 No2:
The best choice is to get one of each.

I have a 9,3x74R double rifle amd I love it.

It is a GREAT hunting rifle.

I have taken a lot of game with it including cape buff and elephant.

I also have talken a lot of game with my 450/400.
I use it for deer, wild pigs, black bear, caribou, used it on a brown bear hunt but did not shoot one, as well as some Zimbabwe Plains game, a cape buff lion and bull elephant.

Both are excellent calibres.

They make a great pair.

Tony's post above is right on target. I have both 9.3X74R,, and a 470NE double rifles, but I'd much rather have a 450/400NE 3" double than the 470NE. I don't hunt elephant, and the 450/400NE is a buffalo killer, yet is much better for an all around rifle for large North American, and Europian game as well.

The 75% rule is a real fine thing for practice, stump shooting from under hunting conditions. The less recoil with the 75% rule ammo in any caliber makes for the easy fireing of many rounds to learn your rifle intamitely. That will pay high dividends, in spades, when the time comes where you ABSOLUTELY NEED to do it right, or die!

I also agree with Tony that the key is to get one of each, for a pair to take to Africa!

.........Good luck with which ever way you go!

What's the 75% rule? Does it mean that if you keep powder the same, and use a bullet weighing 75% as much as the one your rifle is regulated for, it shoot shoot to the same point of aim?

Indy

Yes, basically that is correct.

The advantage is that if you have a big bore double rifle you should shoot it as much as possible.

Since we can hunt deer and pigs, more often than we can hunt buff/elehants, and we do not need a buff/elehant bullet to kill deer and pigs we can get a lighter [75% the weight of the buff/elephant bullet], constructed for the lighter game, and get great kills, with less recoil, with ammo that shoots to the same place as our full power loads.

I use 75% rule with my 450/400 3 inch. I can shoot 300 grain Hawks or 300 grain 405 Winchester bullets (.411) which I size down to .408 for my rifle. These are just loaded over my normal powder charge.

Does the 75% rule apply to the .375 H&H as well?
thanks in advance
Rick

Been trying to talk myself into a double rifle before too long. I like the 450/400 except that the 400 grain load seems too slow. What about a 300 grain load at higher velocity (75% rule) with a scope? Then take the scope off and shoot 400s with iron sights for heavy game. Best of both worlds?

Here's a question. With my .458 Model 70 350 grain bullets shoot several inches LOWER than 450s at 100 yards.

The reason (I am told) is that the 350s are not in the barrel as long, since their velocity is higher, so the rifle does not recoil upward as much before the bullets leave the muzzle.

With a double rifle and the 75% rule, do you notice any elevation change with the two weights of bullet?

The whole point of the 75% rule is that the lighter bullets regulate well AND hit with the sights.

So you 450/400 will hit 300 and 400gr bullets with the iron sights, and the scope.

You could load the 300gr bullets to a higher velocity, but they might n ot regulate and ring to the sights.

foxhound, yes it should work in a 375 H&H DOUBLE if you duplicate the old Cordite loads.

Early British 375 Flanged and 375 H%H doubles were known to shoot 235, 270 and 300gr byllets to the same poing of aim.

This was one of Holland & Hollands selling points. They did use a different charge of Cordite with the different bullets, or at least they claimed they did.

Single barreled rifles do not seem to follow the 75% rule.

It may be because of the higher pressures they operate at.

One of these days I am going to try the older Cordite 375 H&H loads, with the equivalent amount of RL 15 and see what happens.

Indy

What are your loads with the 450 and 350gr bullets?

quote:

Originally posted by Indy:
Here's a question. With my .458 Model 70 350 grain bullets shoot several inches LOWER than 450s at 100 yards.

The reason (I am told) is that the 350s are not in the barrel as long, since their velocity is higher, so the rifle does not recoil upward as much before the bullets leave the muzzle.

With a double rifle and the 75% rule, do you notice any elevation change with the two weights of bullet?

My 75% load shoots a tad lower than full bullet weight loads, but not enough to make a difference when hunting. On the range, the difference is right between the standing 50yd rear sight and the folding 100yd sight.

I don't notice a reduction in recoil with my 75% load, even though physics says its there.

JPK

Indy

JPK's 458 Win Mag is a Double Rifle, and a nice one too.

However you might try his loads in your Bolt 458, and see what they do.

Since originally developing the 75% Rule load I have switched my full bullet weight load, but the new one shoots to the same POA as the old one, though 100fps faster, so I still have two loads that will work.

For that matter, My 450gr NF load shoots with both my 500gr Woodleigh load and my 350gr load.

Happy to share them, but since some fellows took my 450 NF load and switched bullets to Barnes and didn't start low and work up, etc, etc, I will no longer post them on the open forums. Happy to do so by PM though.

Indy, you have my 450NF load already, right? New one or old one? (Based on the NF old style - H 4895 - or new style - AA 2230?)

JPK

In my 450 No2 I have developed full power/full bullet weight loads with IMR 3031, IMR 4831, and RL 15.

With 350gr Hornadays the 75% rule worked with all 3 powders.

quote:

Originally posted by N E 450 No2:
Indy

What are your loads with the 450 and 350gr bullets?

I am using 72 grains of A2230 with the 450s and (don't recall it now because I'm at work but it's a real caseload) grains of H4198 with the 350 TSX.

CAUTION: These work in my rifle in part because I have a lot of freebore. Also, I load the TSX out further, and use a different groove for crimping. This only works if your magazine is long enough.

Chronographed velocities are 2250 and 2600 respectively. I have loaded the 350 TSX to 2700 with no perceptible pressure problems--IN MY RIFLE--but don't need the extra velocity for anything.

Yes, I have JPK's loads from an old post and he was very helpful in putting me on to AA2230 and North Fork 450 grain bullets, though my powder charge is different than his.