Regulating an over/under in 9,3x74R

[Deleted member 13924]

Hi Folks,

I hope you might be able to help advise me on why I'm having so much trouble getting my 9,3x74R over/under to regulate. Perhaps I just haven't tried enough bullet weights/velocity combinations...?

I have been working with 286gr bullets as this is what I imagine the rifle would have been regulated with in 1969 when it was built by Franz Sodia of Ferlach.

I started with some S&B and RWS factory ammo, and got the bottom barrel grouping on the left and top barrel grouping on the right, each barrel is grouping nicely, but the groups are horizontally 2-3 inches apart at 50m.
Using that brass I started reloading with a Highland X bullet, which is a cheap lead core bullet. Played around with velocity (all around 1950 to 2150f/s), but the bottom barrel always groups on the left and top barrel always groups about 3 inches to the right. Depending on velocity the top barrels group might move up above the bottom barrels group, or move below it or be next to it, but always to the right of the bottom barrel.

I then went through a bad batch of factory ammo and had horrible groups and case separation and other fun and games, so I got rid of that whole lot of ammo and have started again from scratch.

I'm now using brand new Hornady brass, and trying an expanding monolithic bullet made locally here in South Africa called a Peregrine VRG-3. It is also 286gr. I specifically choose this bullet because the manufacturers say it is made from copper, which is softer then brass, and is therefor fine for old(er) barrels of double rifles. I have slowly worked it up from 2050f/s to 2130f/s. I have also moved my testing to 30m, as its esier to see, and less distance to walk and mark each shot. (If I can get it to print both barrels an inch apart at 30m, 50m will be fine too)
The end result so far is a lovely tight group from each barrel, but still about 2,5 inches apart.
I have been using a locally produced power called S335 and reached the limit of how much I can load because I'm starting to get a slightly sticky action when opening, so I dont want to push it any faster with this powder/bullet combo.
I am going to change to a slower burning powder called S361. This will give a slower burn and less pressure, with about the same velocity from the same bullet, and might change the "barrel time" enough to let the two barrels print in different places (hopefully closer together!)

My next option after that is to try a lighter bullet...? I am not really too fussed about velocities, I just want the rifle to regulate!

Does anyone have any advice on how to get an over/under to bring its groups closer in a horizontal plane?

What effect might lighter bullets have on where the barrels print?
What effect might higher or lower velocitys have on where the barrens print?

Any constructive advise or suggestions (from folks who have knowledge or experience in regulating doubles) would be most welcomed.

Many thanks.

HB

 

[Longwalker]

If your O/U barrels are shooting apart, (or crossing) to any significant amount horizontally, no load adjustment will fix it. Your load / bullet changes will change the exact timing of the rifle's recoil, and therefore the amount of muzzle rise, and therefore point of impact of each barrel on a vertical plane. But various bullets / powders won't change the side to side convergence. That is one of the reasons O/U are simpler to regulate than SxS rifles. Loads only affect recoil/timing/groups on the vertical plane. If the maker gets the O/U horizontal alignment correct and parallel so that groups from each barrel are on top of each other, all is good and stays good. If not, you need to have the gun re-regulated by a competent gunsmith.
I wasn't satisfied with the regulation in either direction when I bought my used Beretta Silver Sable 9.3x74R, and sent it at some considerable expense to J.J. Perodeau in the USA. now it shoots very well and is not fussy with various loads.

 

[IvW]

Measure the barrel twist rate it may have been regulated for 232 gr loads at higher velocity.

 

[Deleted member 13924]

Hi Folks,
Here is an update of all the info and testing I have done so far.

I have worked out that my rifle has a 1:14 inch twist rate. Not sure if that has any relevance to finding the perfect load, but a least one bullet manufacturer here in South Africa seems to think that the rate of twist will mean that some bullets will be better suited to the gun then other bullets.

I have tried S&B factory ammo, and various hand loaded combinations of bullets/ powders/ and velocities.
I have summarised all of these on 5 pages according to bullet and powered combo.

Have a look and let me know what you think...

Some things worth mentioning are:
1- on almost every target you can easily split the bottom barrels group on the right, and the top barrels group to the left.
2- the earlier testing I did at 70m, but lately I have standardised it to 30m to keep things simple until I have a decent workable load.

The 5 summarised targets are pretty self explanatory.

First I started with S&B factory ammo. Nice group grom the bottom barrel at 70m, but in general, not great through both barrels.

2nd I tried a Highland jacketed lead bullet with S335 powder at various velocities. What is interesting here is that the bottom barrel likes a load of 50,5gr @ just under 2000f/s (even at 70M), but the top barrel seems to like 55gr at 2300f/s. What is also interesting to note, is that with the last load I tested, at the highest velocity, the bottom barrels group moved up considerably in relation to the top barrels group. (when I say a barrel "liked" a load, I mean how tight was the group, and in this case, how close to point of aim was it.)

3rd I tried a Peregrine expanding monolithic of 286gr, still with S335 powder. The best results I achieved was with 54gr S335 (just over 2200f/s). Each barrel gave a very tight group (2 shots touching) and the groups were on the same horizontal plain, but too far apart. The action started to get a little sticky when I tried to open it, so I will not proceed any further (faster) with this bullet/powder combo.

4th I tried the same Peregrine 286gr expanding copper monolithic with a different, slower burning powder, S361. I was hoping to achieve lower pressures with the same velocities, and perhaps horizontally closer groups. The results were not what I was expecting!!! Each barrel produced a lovely group, but velocitys were low and the groups were vertically very far apart. With lessons learnt from the highland bullets (increased velocity moved the bottom barrels group up), I thought I could move the two groups closer together. Horizontally they were closer then I had previously attained. However, when I increased the load by 2gr, there was hardly any difference in velocity, but the action got difficult to open! Fearing high pressures I will not procede any further with this S361 (slow burning powder). Bearing in mind I got 2200f/s from the same bullet with S335 before the action got sticky, but with S361 it was difficult to open at just 1970f/s... If anyone is able to explain how that works to me, please do, I'd love to under stand how the increase in powder from 63gr to 65gr (which is the recommended starting load in Peregrins reloading manual) caused no increase in velocity but a noticeable increase in sticky action/ presure...???

5th, Finally I have tried a 230gr expanding monolithic bullet from GS Custom, with a faster burning powder called S321. I have received the best results so far from this bullet, even though it was just a (carefully) estimated start load. I will now work with this bullet and push it slowly faster and see where the two barrels groups go. I also want to try it with S335 powder.

My last option is to try an even lighter bullet. GS Custom makes a 195gr expanding monolithic, which they recommend for the 9,3x74R. I will try it, but my heart is sad, because the traditional bullet weight for a 9,3 is a 286gr bullet. At 195gr, I feel like I might as well be shooting a 30-06. However, if I can get my rifle to regulate I'll be happy with a 195gr monolithic bullet, or the 230gr mono I'm currently working with.

It is also worth mentioning that GS Custom claim their bullets design has very low friction, using their "drive bands" which create minimum contact with the grooves but still engage the lands, thus lower pressures and higher velocities. Go check out their website, www.gscustom.co.za . They recommend their 230gr bullet be doing around 2700f/s (this is for a 9,3x74R), and their 195gr bullet be doing up to 2900f/s, which they say will still be with in safe pressures. The greatly increased velocity of these expanding monolithic bullet will certainly add some kick to their "lighter weight"!
But if I can get either to regulate with 4 shots in 2 inches at 50m, I'll be very happy
The search for the "regulated load" continues...

HB.

 

[Longwalker]

It looks like you will not be satisfied with load development, because I believe your barrels are not parallel in the vertical plane. The solution is expensive and may be difficult to achieve. You would need to find a competent gunsmith who can re-align the barrels so that they shoot parallel to each other. this requires specialized jigs, and considerable skill in adjusting and soldering the barrel joints and ribs.
One possible hope, that is far cheaper and may be a simpler fix - inspect the muzzle crown of both barrels with a magnifying glass. If the crown of one or both barrels has been damaged, the resulting uneven gas pressure may be pushing the bullet sideways as it exits the bore.
IF one or both of the muzzle crowns are damaged, Re-crowning will return everything to square and perpendicular and should improve convergence of your groups.

 

[IvW]

Velocities are too low to start with. 1 in 14 twist suggest lighter bullets than 286(normal twist rate would be 1 in 10 or 1 in 12 for the heavier bullets anyway).

1 in 14 would suggest something close to 250 gr.

I have somewhere load development done by Mauritz Coetzee(sadly passed on) for a 9.3x74R double rifle, I will have to dig it out so I can share that info with you.

 

[Deleted member 13924]

It looks like you will not be satisfied with load development, because I believe your barrels are not parallel in the vertical plane. The solution is expensive and may be difficult to achieve. You would need to find a competent gunsmith who can re-align the barrels so that they shoot parallel to each other. this requires specialized jigs, and considerable skill in adjusting and soldering the barrel joints and ribs.
One possible hope, that is far cheaper and may be a simpler fix - inspect the muzzle crown of both barrels with a magnifying glass. If the crown of one or both barrels has been damaged, the resulting uneven gas pressure may be pushing the bullet sideways as it exits the bore.
IF one or both of the muzzle crowns are damaged, Re-crowning will return everything to square and perpendicular and should improve convergence of your groups.

Hi Longwalker,
Thanks for the reply.
Hopefully the barrels are not too far out, if they are at all.
I'll continue with the load testing and maybe I'll get lucky.
I have considered having the barrels recrowned, but even at 70M the bullets are not tumbeling, so I dont think that is the problem. But if I get no joy from the load develpment I'll look into the crowns.
Many thanks,
HB.

 

[Deleted member 13924]

Velocities are too low to start with. 1 in 14 twist suggest lighter bullets than 286(normal twist rate would be 1 in 10 or 1 in 12 for the heavier bullets anyway).

1 in 14 would suggest something close to 250 gr.

I have somewhere load development done by Mauritz Coetzee(sadly passed on) for a 9.3x74R double rifle, I will have to dig it out so I can share that info with you.

Hi IvW,
Thanks for the reply.
I know the velocities are low, but these were (fairly conservative) start loads, now I will work them up from there.
The 230gr has given the best results so far, so I'm going to work with that for a while.
If you could find Mr Coetzee's load development data I would greatly appreciate it, thanks
HB.

 

[Deleted member 13924]

We are getting there slowly...

Here is my latest load development with the 230gr HV GS Custom bullet.
The two barrels are slowly coming together, this is the closest I have gotten them so far.
The purple load is now both barrels, two shots each, all in 2 inches at 30m. (extreme spread centre to centre is 39mm)
With an increase in velocity the top barrel has been moving left, closer to the bottom barrel. What is slightly concerning is that the bottom barrels group seems to be opening up slightly, or maybe I just had one bad shot...?
If I can improve on this slightly I might get my desired 4 shots in 2 inches at 50 or 60m
The work continues.
Slowly slowly catch a monkey...

HB.

 

[AZDAVE]

I have shot 3 different 9.3x74 but they were all SxS, and they regulated best when my loads were going 2360-2380fps. the last load with 230gr GS customs is your best and a very acceptable hunting load. I do believe that @IvW may be correct in that your barrels may not be on the exact same plane or that one of the crowns may have some damage. The crowns are a easy fix the adjustment of barrels not so easy and costly. Both of the O/U doubles I have shot were both on the vertical plane and I just needed to work on the correct velocity to get the upper and lower barrel to shoot together. Good luck on your double.

 

[Deleted member 13924]

Progress report...

I tested a few more loads with the 230gr GS Custom bullet and increasing loads of S321. They got slightly better then started moving apart.
So I now have 2 options with this bullet/powder combo...

Option 1 is I can pick one load, which would be 60gr powder (I have not posted a pic of the results, but it was the best) and then play with seating depths and see where it goes,

Or, option two is to take the best load in the bottom barrel and the best load in the top barrel and load each as such. Effectively I will have two loads, the load that performed the best in each barrel.
Now I'm sure there are may out there who will say that is just not cricket! A double rifle should take one load and it should shoot acceptably in both barrels. I would agree with them.
But I must face reality, and it seems my rifles barrels don't point in the same direction for some or other reason.
The solution is to get them re-regulated by a gunsmith. But this is a costly fix, which I cannot afford.

So I have decided to go for option two, and load up two rounds for each barrel. The load that performed best in each barrel during all the testing (closest to POA).
I have given this much thought and the chances of me ever having to face a charging dangerous animal, with this rifle, are very very small.
Besides, I have another rifle which I use for that. And, in this country it is illegal to hunt dangerous game with a 9,3mm anyway, so this rifle has been confined to biltong hunting (plains game). Thus I cannot foresee my self ever being faced with a charge, in a time constrained, under pressure reloading situation with this rifle. I will probably have time to reload and still be cognacent of what I'm doing, and thus get the correct round into the correct barrel for follow up shots, if need be. And with practise and and correct placement of rounds in my ammo belt, it will become second nature.

So I loaded up 4 rounds, and I moved back to 60m, which is the distance I have decided I want this rifle to perform best at and be "regulated" at.
Attached below is the result of 4 shots, 2 from each barrel, from 60m. I think the far right shot was just me.
This group was under 70mm (2,7inches) at 60m. If the far right "flyer" was in fact me, the group would have been under 2 inches at 60m.
I'm happy with that

I will continue to test, with different seating depths of these two loads (as the bullet manufacturer recommends), just to see if the groups close up. But that will have to wait till lock down is finished, because I'm now out of bullets

In the mean time I have acquired some 180gr Impala monolithics which I am going to test tomorrow, just to see what they do in my rifle...
Will post the results when I have them.

HB.

 

[RayAtkinson]

First you not regulating your trying to "sight in"..Regulation is the art of soldering and wrapping the barrels with wire and a shive between the two barrels to move the point of impact, and you regulate the POI with one load and that's what a double rifle shoots..trying to sight in a double with other loads creates the problems you are having..You would have to be darn lucky to find a workable load the way your going at it..

The world of the double rifle is much different than the world of the bolt action sporter..

First you need to call the maker, give them the serial number, and find out what was used to regulate that gun and that will solve your problems, If you have the factory box and papers it will advise you of the regulation load..

Another option is to decide what load or what ammo you want to shoot, then have a double rifle gunsmith re-regulate your gun..David Yale is a great double rifle regulator if you can locate him..Maybe you could talk Butch Searcy into it..Maybe someone on this thread can do it or knows someone who can..

 

[IvW]

First you not regulating your trying to "sight in"..Regulation is the art of soldering and wrapping the barrels with wire and a shive between the two barrels to move the point of impact, and you regulate the POI with one load and that's what a double rifle shoots..trying to sight in a double with other loads creates the problems you are having..You would have to be darn lucky to find a workable load the way your going at it..

The world of the double rifle is much different than the world of the bolt action sporter..

First you need to call the maker, give them the serial number, and find out what was used to regulate that gun and that will solve your problems, If you have the factory box and papers it will advise you of the regulation load..

Another option is to decide what load or what ammo you want to shoot, then have a double rifle gunsmith re-regulate your gun..David Yale is a great double rifle regulator if you can locate him..Maybe you could talk Butch Searcy into it..Maybe someone on this thread can do it or knows someone who can..

David Yale or Butch Searcy to help regulate/develop a load for an O/U double rifle in South Africa......I think this virus is has wider effects than we realize.....

 

[Nhoro]

Just a random thought but how are you shooting-from the bench ? Maybe try shooting off sticks/offhand. See how that goes.

I also notice that your shots are moving closer with increasing velocity and your velocities are a bit on the low side for the bullet weights you have used. If you have pressure signs at low velocities, maybe you have the wrong powder? Move across to something that gives you 2430 fpx with the 285 g and 2560 with 230 gr. those are factory loadings and probably more in line with what the gun was regulated with ?

 

[Red Leg]

Missed this when you first posted.

First of all, an OU double should not shoot side by side groups. Ever. That would indicate a regulation issue. As you no doubt have already surmised, the likelihood of finding a record of the actual ammunition used in regulating this rifle is almost nil. "Franz Sodia" has been reorganized several times since 1969. As others have surmised from the twist, many 9.3x74R rifles intended for European use were regulated with the 250gr bullet. That is where I would have started.

You haven't mentioned anything about condition. A lot can happen with a rifle over five decades. Do the barrels still ring true? Hold them by the forend hook with a finger and tap them with the wooden handle of a hammer. They should ring like a bell. If they clunk, then they are no longer properly joined, and they need to be regulated again. If they ring true, then there is likely a mid-range 9.3 load that will offer better regulation. I would guess the original load was either RWS or Hirtenberger. That said, the side to side distribution has me concerned something or someone happened to this rifle along the way.

If this was a later gun, it is possible that the original regulation was shooting SxS. These days, too many makers simply try to get two bullets in a 3-4 inch circle at fifty yards, call it "regulated" and send it to distribution. But in 1969, a company like Franz Sodia would insure that the regulating ammunition was shooting a tight vertical composite group at 50-70 meters.

I assume finding anyone in South Africa who could competently re-solder and regulate a double rifle would be an iffy thing. If that man does exist, then find the load that shoots most accurately from each barrel, regardless of spread, and use that as the new regulation load.

 

[RayAtkinson]

suggest that you have the GS Custom bullets re-regulated in your gun by a good double rifle gun smith such as DAvid Yale, Butch Searcy if he will do it, and there are more..The gun shoots extremely well with certain loads, just need to bring the groups together, regulation will do that...Monking with a double is from monking with a bolt action for too many years, and it just ain't gonna work on a double to any extent as you can see..

 

[Nhoro]

Maybe before you re-regulate, try Woodleigh FMJ and or the same shaped soft and see what you get. They have the shape of vintage Kynoch rounds and may just work out for you. Many double users load Woodleighs because they regulate.

 

[robert kuester]

I use 54grs of RL15 and 286gr A Frames or the 186gr Woodleigh soft point in my sxs and they regulate perfect!

 

[robert kuester]

Sorry I meant 286 Woodleigh.

 

[Red Leg]

I use 54grs of RL15 and 286gr A Frames or the 186gr Woodleigh soft point in my sxs and they regulate perfect!

Robert that is great news, but it has very little to do with any other SxS or OU.