Hello:
I am trying to work up a load for my Chapuis - I am not having much success with commercial rounds so maybe it's me - I am new at DR altho I shoot SxS shotguns a great deal.
Anyway, I've been working on it and had some success today but don't understand something - at 35 yards I get real nice groups from both barrels. (9.3x74R Chapuis)

At 75 yards the right barrel is spot-on but the left barrel shoots way to the right - at least 6 inches. I loaded 10 rounds last nite and shot them today so this is based on ten rounds of:
H4831 66gr; CCI 200 primer, 286gr bullet

Hotter loads are a lot worse, which is in keeping with what I've read on this forum regarding cross-over

This is with the scope attached (the rifle was factory regulated with the scope) and at 35 yds it shoots the same with or without the scope. I don't see well (cataract surgery) enough to determine this at 75 yds but I think it's behaving the same with or without the scope.

Can someone help diagnose this? I do not have a chronograph.

First thing first...I have rearanged things a bit the way as I see them...

quote:

Originally posted by Oxon:
...at 35 yards I get real nice groups from both barrels. At 75 yards the right barrel is spot-on but the left barrel shoots way to the right - at least 6 inches... This is with the scope attached (the rifle was factory regulated with the scope) and at 35 yds it shoots the same with or without the scope. I don't see well (cataract surgery) enough to determine this at 75 yds but I think it's behaving the same with or without the scope.(9.3x74R Chapuis)

Guessing from 75 yds results that rifle is already crossing at 35 - meaning - right barrel is a "leading one" (that follows the scope) - therefore I guess it is shooting well also at 35, as well as at 100 yds etc...and the left barrel is "the follower", crossing at 35 already and so much more at 75?

quote:

I loaded 10 rounds last nite and shot them today so this is based on ten rounds of:
H4831 66gr; CCI 200 primer, 286gr bullet

Hotter loads are a lot worse, which is in keeping with what I've read on this forum regarding cross-over...Can someone help diagnose this? I do not have a chronograph.

Before all get a chronograph - to determine a Fever you need a thermometer...however it looks like your kid has a fever...saying - barrel time is too short (bullet too light and/or velocity too high)...without chrono data it is all hypothetical - slowing 286gr loads down (a point untill they are above 2300fps? - if not - it is not worth it - re-regulate) or/and get heavier bullet (not many around) 293 gr TUG or 325 gr Oryx come to mind - still keep them above 2200fps to make sence - if not - re-regulate...

Folks, you cannot apply bolt action methods of reloading to double rifles, it just don't work!

First you need to determine what ammo the gun is regulated with then find out the load and you may or may not be able to duplicate it. If you cannot find the load then chronograph it and use that velocity as a guide. Just filling a case with various amounts of various powders and bullets probably won't get you there unless you get real lucky..

Probably the best way to fix a double is let someone re regulate to your prefered bullet weight and velocity.

#1---Contact Chapuis and find out what ammo the gun was regulated with, to include bullet weight, bullet type, and powder charge.

#2---Then either buy the ammo it was regulated with or attempt to duplicate those loads with your handloads. It may take some time, but that's part of the fun of a DR.---Do not give up. Chapuis rifles have a good reputation of being well-built and well-regulated.

#3---Do not send it to a certified capable gunssmith to be re-regulated until you have done your best to copy the original loads. Re-regulation is very expensive. If you did not hand load, I could possibly see the justification. But for someone who hand loads, you have all options at hand.

Mike

For what it's worth. A acquaintance of mine owns a Chapuis double (o/u) in 9,3x74R. It came with a test target shot with RWS 235 gn factory ammo.

Thanks for the interest - I'm very much an amateur when it comes to DRs and also to reloading and appreciate your input.

My Chapuis was allegedly regulated with Norma Oryx 285 gr bullets. No indication of powder.

I have been futzing with this for a year or so now - I have had a lot of other irons in the fire so couldn't really dig into this.

Finally the other day, using IMR 4350 (58gr); PVI 286 gr bullets and CCI 200 primers I got some decent groupings at 75 yds.

I'm feeling a lot better now - I will work around tis range and see what happens.

I tried using commercial-loaded Oryx loads and they just didn't work. That got me paranoid about my shooting.

This is a longer and slower process than I had envisioned but it is very interesting and keeps me occupied (= diverted from productive work!)

Just a story: I once received a very well known brand 9.3 O/U to install a scope with claw mounts.

He was bragging how well it shot.... kind of raised a red flag.

Before doing any work, took it to the range. The lower bbl was spot on a 70 M, top barrel was 13" low.

Sure enough, he then produced the facory target..tiny little group at 70M and ammo was specified.

Got some of the same ammo, with my same results. Needless to say, the gun was promptly returned to the maker overseas

I advised the customer to have the factory install the scope..thereby saving me a BIG headache...but can you imagine the big headache if I hadn't shot it first?

Point is, proof it out with the ammo they claimed to use..you then have a case for warranty

Oxon,
I just bought my wife a Chapuis RGEX in 9.3x74R with 22" barrels. Chapuis screwed up and regulated it with 260gr bullets...pissed JJ off, as he ordered it regulated with 286, per my request. I tried your load of 66gr IMR4831 and a 286 Hornady...it was way hot! 2490fps.
This rifle runs good on 61gr of IMR4831 and the 286 Hornady at 2270fps.
Run yours through a chronograph...I bet you are way fast.
ND

I don't recall ever using IMR4831 - I used 66 gr H4831 which is the minimal load for this powder!

So far the best patterns I've gotten have been with 58 gr IMR4350. Haven't had the chance to play any more with it since.

Curiously, I haven't seen IMR4831 recommended anywhere for the 286gr bullet. Since I'm very new at this I'm sticking with published loads until I get more confident.

Thank you for the info - I've noted it and will give it a try later on - I do have some of the powder - I used it in some .300 WinMags.

Oxon,
The IMR4831 is 1 click faster than H4831 on the powder burn rate charts. They are very, very close in burn rate.
I agree with many others here, that your next step should be running some through a chronograph. Regardless of the published data, some barrels are tighter than others...bullets vary on composition...powders vary from lot to lot...etc... These things can all greatly affect velocity. You need to see how fast you are running. I suspect you will find your current velocity a bit high.
I also have a good load with the 286 slug over 51gr IMR4064 at 2230fps.
Best of luck in your project! Remember, this is the fun part. Once you find the sweet load, it's all over but the shooting.
ND

OXON, I do NOT have a Chapuis, but I do have a Tikka 512SD (O/U). My best loads for a variety of bullets are given below. All loads were based on results at 100 yards.
Woodleigh 286 57 Grs. RL 15
Speer 270 57 grs. IMR 4064
PRVI 285 66 grs. H 414
NP 286 66 grs. H 414
Swift 250 68 grs. H 4350
Speer 270 55 grs. IMR 4064

In general, the above loads will produce 2 bullet holes touching for each barrel, and the barrels shooting 2 inches apart. All at 100 yards.
Now it seems to me you have two problems:
1. Was the gun regulated properly at the factory? If it was then you have to find out what that regulation load was, and then duplicate the velocity and bullet weight. This does NOT mean the gun won't regulate with other bullet weights, but at least you have a starting point.
2. If the gun was not regulated properly at the factory then you have a much different problem. If the gun is new then return it for the appropriate work. If not then pay to have it regulated, or, start load development from scratch, hoping that sometime in the past, the gun was shooting well. I have not bothered much with velocity, but I think that you should be looking in the 2200-2300 fps range depending on the bullet weight.
Hope this helps get you in the ballpark.
Peter.
PS. My gun does have a scope on it.

Peter, thanks for your response to Oxon. Useful information especially the velocity goals.

Tom

Thanks twoseventy. Not gospel, but the reloading tables are not much help. They tell you the velocities of the bullet/powder combination, not what will regulate in your double!
Peter.

The biggest mistake most double rifle shooters make is they don't test the accuracy of each barrel seperately before they start trying to work with their gun..First of all you must understand that SIGHTING IN is not REGULATING. Regulating is done by the gun maker with a hammer, wedges, wire,and solder before the gun leaves the factory..

First step with any double is to fire a group of 4 with the right barrel, then fire a group of 4 with the left barrel, maybe do this two or three times..Now the "LEAST ACCURATE" barrel is the "BEST" that particular rifle will shoot and thats a FACT, no varible here....

So now that you know your rifles capability, you can start finding a load that will duplicate your WORST BARREL test load and now your a happy camper. Now you can sight your gun in, wit your worst accuracy load, because you know that is the best it will do for now. All you have to do now is sight the gun in with a hammer and a punch wacking the sights one way or another and lifting them up and down or filing a too high sight down to zero! I usually zero a double at 75 yards..But you may want to tweak a little more out of it.

You may be able or even have to change your powder load a bit up or down in that if its crossing at 75 then your velocity is too fast, so you must back off this load a grain at a time until it is not crossing or is within the area of your worst barrel group. It the spread is wide of crossing over beyond the size of that worse group then you must add a tad of powder one grain at a time until it comes together.

Its a bit confusing to the newbe but once you figure it out you will be a happy as a pig in poop, or you will be a bolt action fan the remainder of your life.

Doubles are finaky to say the least, but they are wonderful guns and once they are sighted in with one load, never change them is my opinnion. I see no need to monkey with a double that is shooting 2 inch (right left, right left) groups to point of aim.

Also pay no attention to the rumors that are out there..such as you must shoot them Rightk, left, right left...every double I have shot, shot the same by pulling the rear trigger first then the right or backwards from the regulator. and you will not double a double by pulling the rear trigger first..

I also have no problems with using IMR-4831 in any double or North fork monolithic bullets for that matter. also frowned upon by some..The world of the double is shaded in myths and falsehoods, and folks who believe everything they read. It is a cornocopia of black magic passed on from father to son. In reality it's a wonderful gun and common since is the answer.

Ray, thank you for that excellent writ-up. That, along with the many other helpful suggestions has gotten me on the road with my 9.3 Chapuis! I'm using 285gr Oryx bullets, allegedly the round the gun was regulated wth. I seem to get the best results (so far) with 58 gr IMR4350. The right barrel is relatively insensitive to load or bullet.

This morning I shot some 59 grain loads (upped the charge by one grain) and four rounds from the right barrel were within 2-inches at 75 yds - really nice tight pattern.

The left barrel shot all over the place (mostly way to the left). The pattern was terrible - it wasn't that bad just one grain lower seems to have made a huge difference.

Shouldn't a faster speed move the left barrel's shot over to the right?

Can the increase in velocity have caused the pattern to go real bad in the left barrel?

quote:

Originally posted by Oxon:
Can the increase in velocity have caused the pattern to go real bad in the left barrel?

Yes.

My 9,3x74R Chapuis was factory regulated, iron sights with the RWS 293gr TUG.

I have used a bunch of different factory ammo in it, with bullets from the 232 Vulcan, to the 293 TUG as well as several different bullets reloaded.
It does shoot some better than others, but I have never shot a load that I could not hunt with accuracy wise...

My main loads consist of 286 gr Woodleigh Soft and Solids, and the 286 gr Nosler Partition, and the 285gr Hawk with the .035 jacket.

I use 65gr of IMR 4831. I do seat my bullets just a little farther than factory OAL.

My velocities are @ 2225fps. I have killed a bunch of game with these loads including giraffe, bears, cape buff and and elephant.

All the above bullets hit close enough together to 250 yards, that I do not worry about it.

At 300 yards the pointed Nosler Partitions shoot a few inches higher...

Iron sight or scope it does not make any difference in zero or regulation, at least not enough to matter in hunting. I have killed game out to 300+ yards with this rifle and these loads. With whitnesses, on video

Here is a hint, if your 9,3 double shoots a right and a left, and another right and a left into 4" or less at 100 yards, it is a "tackdriver double".

If it shoots a 4 shot group into 6" or less at 100 yards then you are good to go.

Here is another hint, shoot your double rifle at 50 yards off hand, and at 100 yards from sticks and knelling,under "hunting speed", and then shoot you super accurate bolt rifle from the same positions, same speed.
[There are no benches in the hunting woods/bush].
Most likely there will not be enough difference to matter.

If you can hit a 9" pie pan at 100 yards every time offhand or even off sticks, your PH will Love you.

Hi guys first post.I just got back a month ago from Zimbabwa got a nice Cape Buffalo with my Chapuis 9.3x74R nice 3 inch hole through his heart and a very nice Impala with a Zoli 12ga/6.5x57R.As to a regulated load for the 9.3 I was getting dead on at 50 yards and always both barrels in 3inches at 100 yards.I tried half a dozen powders and settled on R15 55gr with a 286 gr barnes TSX and 53.5 gr with a286 gr barnes banded solid(Chapuis said no problem with Barnes bullets).As an aside I'm now up in the High Arctic working as the most northerly float pilot in the world and as a fishing guide,we start hunting Muskox and Cariboo Aug 18 until the ice sends us south.
Take care.Bill Brady

This has been a very helpful thread to me. Last Sunday I finally got very, very close and may just leave it for a while. With the factor scope each barrel will now shoot 2-inch groups at 75 yards.

There is a bit of cross-over but it is trivial and I will futz with it when the weather cools a bit - it's 100 today already in Vermont!

I found the exercise of shooting the barrels at different targets VERY helpful and I thank you for that suggestion.

I also noticed a day-after-day deterioration of the left barrel grouping and it finally dawned on me that there was probably some crap in the barrel and I scrubbed it like mad and that made a huge difference. Real tight groups now.

The Chapuis is a fun rifle to play with and I'm glad I took the plunge and began to reload for it.

Thanks again, guys, for sharing your knowldege!

ttt