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Rell
.375 member


Reged: 03/12/04
Posts: 642
Loc: Oyster Bay, NY, USA
7x65r Chapuis DR regulation issues.
      #253548 - 15/09/14 06:13 AM

My Chapuis SxS in 7x65r is giving me a bit of trouble. It's suppose to be regulated with Norma 156 gr Orynx factory loads, but it shoots about 6 inch groups with the factory load.

JJ at Champlin is going to re-regulate it and suggested hand loads as factory ammo is really hard to come by. I have 1000 156gr Norma Orynx and lots of Norma brass. I can't find much load data for any North American powder. The factory load is suppose to do 2730fps, at the muzzle it does 2650fps in my rifle.

On Chuck Hawks website he shows 49.4grs of IMR4831 to do 2500fps. That's all I got.

Any pet loads out there?

--------------------
450-400, 9.3x74r and 7x65r.

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granhaven
.224 member


Reged: 30/12/08
Posts: 44
Loc: Denmark
Re: 7x65r Chapuis DR regulation issues. [Re: Rell]
      #253659 - 18/09/14 06:25 AM

Two comments,

Firstly the discrepancy in speed between the measured and the speed printed in the documentation is quite commonly observed, you may want to verify the barrel length.
Norma loads are measured with 24" or 61 cm, which is probably more than your Chapuis ( 60 cm )

The 156 grains oryx in 7mm from Norma is in my experience to hard and will not expand properly at the speeed obtainable in your double rifle. I suspect that it was created for the 7mm remmington magnum speed range. I have shoot a number of Boars and Red deer with the Norma Oryx and am not too happy with the result

156 gr norma oryx C.O.L.3,268”
powder min vel Max Vel
Norma 204 49.0 2428 51.5 2674
Norma MRP 52.0 2536 54.9 2720


The quest for finding a load that will shoot reasonable together AND have the speed required for proper bullet expansion is both time consuming and expensive.

The first question is if the first and second barrel keep their bullets reasonable together, this is best tested with two paper targets 50 cm apart. please remember to shoot standing so that the recoil and barrel movement simulates a hunting situation.

The time difference between the first and second shoot must be within 2-3 seconds. Also remember to let the barrels cool 15- 30 minutes between two consecutive shots from the same barrel.

You also may want to check the trigger pull weight, I assume that you shoot the first shot with the set trigger, and the second without , which in my experience is one of the root causes of bad grouping.

Keep posting the test results

Regards,

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Igorrock
.400 member


Reged: 01/03/07
Posts: 1636
Loc: Finland
Re: 7x65r Chapuis DR regulation issues. [Re: granhaven]
      #253667 - 18/09/14 05:02 PM

Quote:

The 156 grains oryx in 7mm from Norma is in my experience to hard and will not expand properly at the speeed obtainable in your double rifle. I suspect that it was created for the 7mm remmington magnum speed range. I have shoot a number of Boars and Red deer with the Norma Oryx and am not too happy with the result

Strange, my friend shoot that same bullet with 7x57 without any problem.

--------------------
http://promaakari.wordpress.com/

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HeymSR20
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Reged: 23/11/11
Posts: 244
Loc: Scotland
Re: 7x65r Chapuis DR regulation issues. [Re: Igorrock]
      #253784 - 20/09/14 08:47 PM

If you send me a PM I can let you have load data for the 7x65r for a number of powders including IMR 4831 and 4350. The Hornady manual has quite a few loads for a range of bullets from 139 up to the 173g.

I would give some of these a go and you might get lucky and replicate the factory regulation.

I suspect that the factory regulation would be done with RWs 173gn load. An email or a call to Chapuis would be worth a try.

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dpcd67
.224 member


Reged: 08/07/13
Posts: 25
Loc: USA
Re: 7x65r Chapuis DR regulation issues. [Re: HeymSR20]
      #256283 - 05/11/14 07:01 AM

The regulation load should be marked on your factory test target. In any case, if you have to get it re-regulated with hand loads, don't be too concerned with a hundred fps; it won't matter on game at the ranges that DRs are used. I have not used the Norma bullets you have though.

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gungadoug
.333 member


Reged: 13/08/12
Posts: 285
Loc: NM
Re: 7x65r Chapuis DR regulation issues. [Re: dpcd67]
      #256288 - 05/11/14 10:57 AM

Don't worry about it. Pick a load and bullet you like, and JJ will do the rest. BTW, he has moved recently, and has a new phone #. Still doing work for Champlin, but not in the same building or city. www.jjperodeau.com

Best in the business, IMHO Doug

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CommandCar
.333 member


Reged: 18/09/10
Posts: 292
Loc: East Coast, USA
Re: 7x65r Chapuis DR regulation issues. [Re: Rell]
      #256985 - 19/11/14 10:25 PM

Norma has data on their site: http://www.norma.cc/en/Ammunition-Academy/Loading-Data/

I use Reloader 19 in my F. Kettner. The load is from a German RWS manual, "Wiederladen" that Old Western Scrounger sold in the past. Some of the RWS, Norma and Reloader series powders are interchangeable. For instance, it is my understanding that Norma 204 is or was Reloader 19 and Norma MRP is or was Reloader 22. I WILL NOT STAND BEHIND THIS LAST STATEMENT. Please do your own research before attempting any powder substitutions!

Hornady does have data, with a note to reduce loads when used in break open guns. 7x65 R is a lower pressure version of the 7x64 which is almost identical to the 280 Remington. Combinations that work in these 2 cartridges would be interesting to review for background comparison only, as they would almost certainly be of too high pressure.

Feel free to PM me for more discussion.

Good Luck.

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