I wanted to get an opinion from the AR community about the max load for IMR4831 in a .470. One source lists the max load as 106 grains and another 108 grains (for a 500 grn bullet).

I have been working up loads for my .470 starting at 100 grains of IMR4831 with Woodleigh softs and increasing by 1 grain each time. The problem is that the individual barrel groups are good but the barrels are shooting apart. I understand that this usually means more velocity is needed. My concern is that I haven't seen a real difference between the 100 grain load I have started with and the 103 grain loads I just shot today.

I have been cautious in my approach by increasing by 1 grain at a time but I'm wondering if I'm being too cautious. I'm debating going from 103 grains to 105 grains for my next batch but I want to see what the collective wisdom is on the max load.

I do have some RL-15 powder I could try but for some reason using filler scares me a little...

106 grains of IMR4831 is the 470 load with a 500 grain bullet. Hard to do any better. Every gun is an individual so you may be at 105 to 108 grs to bring the barrels together. The Double Rifle Bullet of The Future thread has lots of good data to see. Michael458 and myself tested every bullet available in the 470 using IMR4831 plus some other powders.

The standard formula for IMR 4831 in double rifles is Grains of Cordite times 1.33 equals grains of IMR 4831.

The 470 was originaly loaded with 75 grains of Cordite. SDo 75 times 1.33 equals 99.75 grains of IMR 4831.

With a 470 I would start there and work up one grain at a time, checking for regulation, and pressure signs including sticky opening.

If you are getting any sticky opening, your loads are too "hot".

For Reloader 15 the formula is grains of Cordite times 1.19. so that equals 89.25 grains of RL 15. That is where you start.

There is NO FEAR with using a filler, as long as it is either Dacron, or foam that is COMPRESSED between the bullet and the powder.

I have fired several thousand rounds in double rifles with a COMPRESSED filler WITH NO PROBLEMS. I shot some just today...

This is assuming that your double rifle was regulated PROPERLY when it was first built, and was not MONKEYED with since...

I do NOT care, WHAT your strain gauge shows, WHAT your computer progrqm says, or WHAT load your buddy or the internet gives you... IF you double is sticky to open you have too much back thrust, ie your load with that brass is too "hot".

New made doubles might take a little bit less powder, as their chambers and barrels tend to be a little tighter, but I have NEVER seen any older British double rifle not conform to these rules...

iirc, Butch told me to load 106gr with softs, and 104 with solids in mine.

My 470 Evans regulates great with 102 grs of IMR 4831 with Woodleigh softs and 100 grs of IMR 4831 with Woodleigh solids. This is out of 28 inch barrels.

Be aware that individual lots of IMR 4831 may require differing amounts to regulate in your double since there can be significant lot to lot differences when you are loading such a large (relative) amount of the powder. It pays to be enough 4831 of the same lot to avoid the hassle.

I use R-15 as well in different double rifles with filler and have had no issues but this 470 prefers 4831.

Good Luck!

If you try RL15, I would start at 84 or 85gr since it can be volatile from lot to lot. With the current lot of RL15, I am getting 2160fps with 87gr and 500gr Woodleigh softs and 86gr with solids. At 90 degrees, the softs are clocking in at 2200fps in my Merkel.

I am loading 106gr of IMR4831 with 500gr TSX's in my Searcy and they are running 2150-2160. I use that same load with CEB's in both the Merkel and Searcy.

Thanks to every one for their replies. I finally found the "sweet spot" at 105 grains of IMR4831.
I was getting a little discouraged because starting at 100 grains and going up by one grain increments there was no change in the distance the left and right barrel were shooting apart. The individual barrel groups were always good but they never got closer together.

When I loaded 105 grains behind some Woodleigh softs, PRESTO, the groups came together. I couldn't believe that one grain of powder could do it.

The CEB thread made for some interesting reading and I made some notes that apply to loads for the .470.

Another option is to use H-4831. I like it because it is a temperature extreme powder. A charge of 109 or 110 grains of H-4831 will print to the same point of impact with even tighter groups in my 470 than 106 grains of IMR-4831.

465H&H

I'm sold on IMR-4831..Don't be looking for max laods in a double, that's bolt action business..Look at zero and group size..start with 103 and work up when you dead center at 75 yards that's your load for that rifle..group size is determined by shooting a 4 shot group at 75 yards with each barrel and note this: A double will only shoot as good as the worst barrel grouped. That statement seems to stun most double rifle experts to no end!

So what do you do if groups are good with multiple powders and bullets brand/types, but groups are 5" to 6" low at 50 yards? This is a Merkel 470 which is dead on with factory loads. I've tried duplicating velocities, but it doesn't seem to help point of impact with the sights. Is it about time to have the sights worked on? Factory velocities were 2185 fps over my chrono. Thanks, not trying to hijack thread, but this goes along with some of the things I'm experiencing.

[QUOTE]Originally posted by Kurick1:
So what do you do if groups are good with multiple powders and bullets brand/types, but groups are 5" to 6" low at 50 yards? This is a Merkel 470 which is dead on with factory loads. I've tried duplicating velocities, but it doesn't seem to help point of impact with the sights. Is it about time to have the sights worked on? Factory velocities were 2185 fps over my chrono. Thanks, not trying to hijack thread, but this goes along with some of the things I'm experiencing.[/QUOTE

I'd file down the front sight a bit.
Cal

Kurick1...Are you loading the same bullet in your handloads as the factory ammo? My Merkel in 470 will shoot to the same point of impact with RL15 and IMR4831 with about any 500gr bullet. I used to own a Merkel in 500NE that would shoot great with IMR4350 and not close with RL15 didn't matter the bullet. My Searcy in 470 does not shoot Woodleighs to the same point of impact as Hornady, TSX's or CEB's regardless of powder.

quote:

Originally posted by cal pappas:
[QUOTE]Originally posted by Kurick1:
So what do you do if groups are good with multiple powders and bullets brand/types, but groups are 5" to 6" low at 50 yards? This is a Merkel 470 which is dead on with factory loads. I've tried duplicating velocities, but it doesn't seem to help point of impact with the sights. Is it about time to have the sights worked on? Factory velocities were 2185 fps over my chrono. Thanks, not trying to hijack thread, but this goes along with some of the things I'm experiencing.[/QUOTE

I'd file down the front sight a bit.
Cal

Cal,

I've experienced this with several Merkels that group perfectly but shoot low. Each time I worked on the front sight or replaced it.

Mike

Sorry for the late reply, was out traveling. I was use the Federal Factory ammo with the trophy bonded bear claw I believe. I haven't ever been able to find that bullet on the reloaders market, so have tried Barnes, Hornady Softs and solids(solids were tough to group), now I'm using Woodleighs. I am using the Hogdon H4831SC, is IMR4831 different enough to purchase?

quote:

Originally posted by rxgremlin:
I wanted to get an opinion from the AR community about the max load for IMR4831 in a .470. One source lists the max load as 106 grains and another 108 grains (for a 500 grn bullet).

I have been working up loads for my .470 starting at 100 grains of IMR4831 with Woodleigh softs and increasing by 1 grain each time. The problem is that the individual barrel groups are good but the barrels are shooting apart. I understand that this usually means more velocity is needed. My concern is that I haven't seen a real difference between the 100 grain load I have started with and the 103 grain loads I just shot today.

I have been cautious in my approach by increasing by 1 grain at a time but I'm wondering if I'm being too cautious. I'm debating going from 103 grains to 105 grains for my next batch but I want to see what the collective wisdom is on the max load.

I do have some RL-15 powder I could try but for some reason using filler scares me a little...

What velocity are you getting with the 103 grain load? I have found it is not uncommon to not see a whole lot of improvement in the barrel spread until you get to the right velocity or close to it. Then in my experience they start crossing quickly after the right load/velocity is reached. At 103 grains I would not be surprised if you are at 2050fps or below.

I'm a huge fan of RL15 used with Backer Rod. But there is nothing wrong with using IMR4831 either, other than increased recoil.

Mac,

The truth is I don't know what the velocity is because I wasn't chronographing the loads. The range I use don't allow them. I was working up the loads one grain at a time until the groups came together. I was just surprised that a grain would suddenly bring groups 4 inches apart together. I expected that every grain that I increased the load would progressively move the barrel groups together but it didn't happen that way. There was no change at all until I loaded 105 grains and then magically the groups came together.

Have you been able to repeat your results with the 105 grain load? Like you said, a grain of powder in a 100+ grain capacity case isn't much of a change. In most of the reloading I have done, a group that is suddenly significantly better is usually an anomaly. I occasionally have found a suddenly better load to be consistent, but it isn't the norm for me.

My first thought was that it was a fluke until I shot a second group and a third.

The other strange thing is that I tried some Hornady DGS with 105 grains and it grouped the same. It even groups the same shooting offhand (all the load development had been off the bench
with only my support hand on the bag).

Before this the gun would ALWAYS shoot apart no matter what. I tried factory Hornady DGS and DGX ammo plus the reloaded Woodleighs.

I don't know why but the gun seems to like 105 grains of IMR4831 so I'm sticking to that and now working on shooting offhand only.

That is good to hear. It is obviously the right load. My 450 likes to cross at 50 yds, which irritates me. Before I send it to Aaron to be re-regulated, I'll mess with loads some more. I might find that one magic grain that gives me what I want.