question for those who actually own, have fired and have handloaded for these rifles, what have you found to be the most accurate load and shoots closest to POA.

only interested in opinions from those who fit the criteria. don't need theories; i know theories.

the 450/400's i've loaded so far, and the components i have, have all been with woodleigh 400gr soft nose, federal 215's and IMR4831.

Roger

Will, JJ Perodeau probably knows what the regulation load is for your Chapuis.

So, how did your loads shoot? I assume, not all that well, or you wouldn't ask the question.
I have found that 4831 is sometimes too slow, and the DRs I have used it in, will cross sometimes. So you need a faster powder; remember that regulation is not merely a function of velocity; it is also how the bullet gets to that velocity, which is a function of burn rate. If you go to RL15 or similar, if it is crossing, it might come back together. I have loaded for, and fired, several 450-400s.
This is not a theory, so you can read it. If you think it is a theory, then don't read it.

quote:

So, how did your loads shoot? I assume, not all that well, or you wouldn't ask the question.

well, since i'd never actually shot it until today - after posting this question - your assumption didn't have a lot of validity. i never said i'd loaded for this particular rifle. there've been others. that's why i had components on hand. I've only owned this rifle 2 days.

and the loads i shot today actually did very well, as well as i can hold at 100 yds with open sights and almost as well as my scope sighted no.1 in the same chambering.

I was really hoping for some actual loads from peopl who'd loaded for and fired this particular chambering in this particular rifle but this worked.

Roger

If your double rifle is crossing, the proper thing to do is cut backk one grain at a time until it returns..

Keep in mind that an double will only shoot as good as the "WORST barrel"..So you must determine that by shooting several groups with each barrel to find the rifles capability and go from there..Many folks have never figured this out..

IMR or H 4831 generally works with most doubles, but 4350 and RL-22 have worked for me on rare ocassions better than 4831. Some claim less recoil with 4350 but I never could tell any difference. My primary rifle in Africa for many years was the 450-400 both 3" and 3.5"..Never found them lacking on any DG. The world of the double rifle is full of old wives tales..and what applies with bolt rifles has nothing to do with doubles.

find your worst barrel, that is your goal and your only option for accuracy, if it spreads add a grain at a time, if it crosses back off a grain at a time...what load someone else uses is of no interest to you!! short of luck..

Test your patterns with each individul barrel and what powders you chose, find the worst barrel and go from there.. when done "sight in with the iron sights" and you have learned the difference between "owner regulating and sighting in" The maker should have done all this for you but that is normally a ball park figure as we all see the sight differently so one must do it himself..

If you must start with 84 to 80 grs ofH4831
81 tp 85grs IMR-4831

87 to 71.5 of RL-22

RL-15 formula is 1.19 x the cordite loads for a starting load.

Fed 215s, 400 gr bullets quoted loads for the 450-400 3" subtract 3 grs for the 3.5"and go from there.

these worked for me in a number of 450-400s, maybe for you who knows?but should be close, as I can recommend..

Hope this helps.

Thanks Ray, useful stuff. They're crossing at 100 yds, but it's uniform. the Right barrel was more accurate by about a third.

One reason I was hoping for loads people had actually used was, the A-Square manuals starting loads are greater than Hornady's maximum. That's a pretty big spread. Of course, Alphin give pressure data and it isn't much pressure so there's plenty of room, especially in a modern firearm. I started with 78grains and will try going up.

Thanks again,
Roger

Roger, I've got nothing useful to add on topic or to Ray's excellent advice above and sold my last 450/400 around 15 years ago, but I do have several series of reloading books going back to the 70s through today and noticed as you did that today's max loads are often less, some times by a few grains, than the starting loads of old with the same bullet, same powder, same primer, etc.

Everyone likes to blame lawyers, but I tend to go with the more modern data for two reasons. First, testing is far, far cheaper today than in say the copper crusher day, and as a result many mnay more rounds of a given load can economically be tested to sleuth out anomalies, rare excursions, sensitivity to angle, temp, etc that you just don't discover from firing 10 rounds in a pressure gun in a room temp lab-type setting. And secondly because despite the best efforts the same powders can vary over time, as say the ABC-3931 line gets moved from NJ to a new plant in TX, old equipment gets replaced, etc, not just lot to lot variation. I'll get off my soap box now.

One of the many reasons I like loading for doubles is they are generally low pressure to begin with and have a big margin built in as you tweak things to get the perfect load for you. What great fun. Please share what you find works best for your Chapuis!

Bob

My 450/400 is a Heym. In my experience loading for the Heym, and my Searcy 450 NE, IMR 4831 is easier to work with and generally more accurate than H4831.

The load I settled on for the 450/400 was a 400 grain bullet, Federal 215M primer, and 76 grains of IMR 4831.

Every double is different. What load regulates in one doesn’t mean it will regulate in another.

Start low on powder, post two targets, one for the right barrel and one for the left. Slowly increase the loads (I go 2 grains at a time) and watch the loads/barrels come together.

Definitely a faster powder will give less recoil, because you use less of it, and powder is a contributor to recoil. This is important in DRs, due to muzzle flip, caused by recoil, is the phenomenon by which they are regulated. And I have built DRs and regulated them.
My Krieghoff 450-400 regulates perfectly with 74 4350; at 2050 FPS. It will not shoot with 4831 at all.
My 450 NE Searcy regulates with 96/4831, and will not shoot with anything else.
I had another 450 once, that was the opposite; with 4831 it would shoot apart, badly. Too much muzzle flip with the slower powder, albeit, exactly the same velocity. It ain't just velocity that makes regulation, contrary to popular belief.
So, even though many powders will give 2050 fps velocity, that doesn't mean they will regulate; which is why no one can ever give someone else a load for a double rifle. Each is different and regulating them is more sorcery than usual rifle load development.
I have also owned 4 Chapuis DRs; my current one is a 9.3 with barrels that you can move yourself; although it will stack bullets on top of one another at 50 yards with the same loads I use in my Kriefhoff 9.3.
Also, I never bother to "group" each barrel. Waste of time; after all, if you have one barrel that shoots that much worse than the other, that defeats the purpose of having a double rifle in the first place. They come as a set and are fired as a set; I never shoot just one barrel.

quote:

Originally posted by dpcd:
Definitely a faster powder will give less recoil, because you use less of it, and powder is a contributor to recoil. This is important in DRs, due to muzzle flip, caused by recoil, is the phenomenon by which they are regulated. And I have built DRs and regulated them.
My Krieghoff 450-400 regulates perfectly with 74 4350; at 2050 FPS. It will not shoot with 4831 at all.
My 450 NE Searcy regulates with 96/4831, and will not shoot with anything else.
I had another 450 once, that was the opposite; with 4831 it would shoot apart, badly. Too much muzzle flip with the slower powder, albeit, exactly the same velocity. It ain't just velocity that makes regulation, contrary to popular belief.
So, even though many powders will give 2050 fps velocity, that doesn't mean they will regulate; which is why no one can ever give someone else a load for a double rifle. Each is different and regulating them is more sorcery than usual rifle load development.
I have also owned 4 Chapuis DRs; my current one is a 9.3 with barrels that you can move yourself; although it will stack bullets on top of one another at 50 yards with the same loads I use in my Kriefhoff 9.3.
Also, I never bother to "group" each barrel. Waste of time; after all, if you have one barrel that shoots that much worse than the other, that defeats the purpose of having a double rifle in the first place. They come as a set and are fired as a set; I never shoot just one barrel.

I note Ray espouses checking the grouping ability of each barrel but you do not. How does anyone know if the ammunition they have, factory or reloads, is capable of grouping or any sort of accuracy?

I can't imagine anyone trying to set a scope or open sights on any rifle if their ammo prints randomly all over the target. Although some don't expect doubles to shoot as accurately as other rifle types however trying to regulate a gun with ammo of an unknown quality would be a lesson in frustration surely?

Double rifles come as a set of barrels. Once you get a proper regulation load, you will immediately know if one barrel is worse than the other. Modern doubles are regulated to be within two inches at 50 meters. You will know which barrel can't do that. Because all new DRs are fired at the factory; and you get the test target; they definitely won't let a bad barrel out. These rifles are not two rifles; they are one. If you are hitting "randomly" all over the target, you have bigger problems that need to be addressed.
Perhaps if you had a well worn vintage double, it would show one barrel much worse than the other, but newly made ones, won't. Come on over and we can shoot some double rifles.
Yes, unknown ammo can be frustrating, but again, both barrels have to shoot within the regulation specs (and most new rifles come with a target). You will quickly know if one barrel is "bad". I have never seen that on a new double.
If you develop a load for one barrel, like you do for a bolt action, and it doesn't regulate, that is a complete waste.
I can show you all this.
So, yes, shooting it like it is two rifles, is a waste of time and ammo, and proves nothing.
Sorry, I just noticed you are in NZ; but if you ever get here, we will go to the range and shoot some double rifles.

Thanks for offer to shoot some doubles, good answers to my queries. Although I have never owned doubles I have shot some while in West Germany many years ago. I got to shoot a beautiful H&H double hammer gun in 303 British on a range. I recall it shot very well not that I knew anything back then about regulation of doubles.
My German friend who I was staying with had a little Belgium FN double in what I noted down as 10.75 x 47G (had the concave Mauser case head but I maybe wrong about the exact nomenclature) for which we were swaging down 265gr 44 calibre bullets. On my return and his and his wife's immigration to NZ we played around with this double again using R905 powder for a MV of 1588fps. It seemed to regulate well enough with this load, again I didn't know much about the process just assumed both barrels pointed to the same place more or less like a shotgun

Yes, you have to size down 44 caliber bullets to fit into the 10.75mm; .429/.430, down to .423.
And you are right, DR barrels do not, and cannot, point to the a predetermined point in space, nor can they be parallel. If that were possible, they would be easy to make. they have to converge, so that during the recoil cycle, the rifle jumps up and to the right and left (not at the same rate or direction), consequently flipping the bullets out and into one place, at whatever point the guy who is regulating it decides, but it is usually at 50 yards. Not to say they won't shoot at farther distances.
That is also why your stance and grip on the rifle is vitally important; lock them down in your bench rest position on bags, and they will cross every time. And all that changes with caliber; light small calibers are less sensitive to that. Heavy recoiling ones, are very sensitive to hold. As I said, it is not a science, it is akin to witchcraft and sorcery, making, loading, and shooting double rifles.