Well the experiments continue.

Yesterday I tested a ladder of loads of H414 w/ 286 Privi Partisan bullets. I started at 65.5gr and increased the charge by .5grs loading four rounds of each load until I reached 67.5grs. (68grs is max.)

The test began with a "cleaned" rifle, bore oiled and dry. Firing was from 50yds except as noted. All kinds of interesting (and puzzling) data was obtained.

Velocities in fps:

Right Charge Left Average
1-2309 65.5gr 2-2263
3-2270 65.5gr 4-2230 2268
5-2339 66.0gr 6-2247
7-2299 66.0gr 8-2212 2276
9-2277 66.5gr 10-2253
11-2293 66.5gr 12-2245 2267
13-2324 67.0gr 14-2257
15-2314 67.0gr 16-2286 2295
17-2273 67.5gr 18-2287 2280
19&20 fired at 100yds and not chronographed

First, from this test and the preceding one with 4064, the right barrel consistently is faster than the left barrel. In only one firing (17,18) was the reverse true. Differences in velocity range from approx 25fps to 90fps. Is this normal; is this the result of more bullets fired through the right barrel (trigger 1)?


Second, velocities did not increase as one might expect with increases in powder charge. (Charges were double weighed and accurate.) I do not have a crimping die for this cartridge, and I am using slight pressure to crimp the case. Although I try to limit neck lube, the differences may reflect some residual present and variance in crimp. I have found this to impact velocity in other cartridges. Any suggestions or observations?

When the groups of four shots are connected, the four shot groups look like this illustration taken from the actual targets and color coded for clarity. The "dot reticle" indicates point of aim (POA). Please note the 66gr group is not included because of a "called" pull which grossly distorts the data. It generally appears the 66gr loads would have been under or on the POA.



The initial 65.5gr loading would seem "high," notwithstanding its velocity which is not all that different from the second, 66gr loading mentioned above. The third, 66.5 loading had essentially the same velocity as the first, but was below the POA. (Size of the group may be the result of a atrocious trigger pull on the rifle.) Lastly, the last four shot group, 67gr, was just below the POA and relatively tight which may be chance more than skill.

In re the two round fired at 100yds: one impacted the target about six inches below the POA and to the right; the other was six inches lower and directly under the POA. I unfortunately did not note which shot was from which barrel.

Question: Which would you follow up on?? I think the 67gr load which provides a bullet strike right behind the front sight and velocities right at 2300fps.

Question: I am rethinking my sizing and crimping regimen. I think I am going to neck size only and not bring the die down far enough to set the shoulder back because I noticed that if I bring the die down to the base of the neck, the edge of the die begins to reform the shoulder. I also think I must get a Lee crimp die ASAP. Comment??

Question: Given the bullet drop at 100yds and the relatively tight group of several of the loadings, and the two scopes which came with the rifle, I wonder I would not be well served to find my load and then adjust the scope(s) to it??

Last question: What is you experience with the 286gr bullet (I plan to use Partitions for softs and Woodleighs for solids) at 2300fps?? I generally get about 100fps more from my 9.3x62, and it kills like Thor's hammer.

Again, I want to thank those of you who have provided input into this work. It has been invaluable and saved me much time, money and aggravation. I truly appreciate the time you have taken to read my reports and comment. Kudude

Load 20 rounds with the PP bullet with 65.5 and 67 grains of powder.

Shoot 10 at 50 yards and 10 at 100 yards with each powder charge.
Keep track of left and right shots.
Show us the targets. Fliers and all.
Mark all called flyers.

The difference in velocity between the two barrels is within normal paramaters.

Be sure you resize the brass so that the rounds go into the chambers easily, as this is a hunting rifle and not a bench queen.

I also assume you are using an up right body position with your hadn gripping the forearm in the normal fashion and NO rear bag.

Stack up sand bags a foot high on the bench if necessary.

Shoot your favorite "accurate" bolt rifle with similar recoil the SAME WAY on the SAME DAY and show us those groups as well.

My 286gr loads are under 2225fps, I have not had any trouble killing cape buff, elephant, giraffe, and all other manner of game with my 9,3x74R.

NE450,

Shooting technique is as you described.

I could shoot my favorite 9.3x62 which is a fair approximation, but I must warn you that it is extremely accurate, and an unfair comparison to the Merkel in those terms.

Are you suggestion 20rds of 65.5 and 20rds of 67, with 10 of each fired at 50 and 100yds??

Thanks. Kudude

The first thing you need to do is shoot several 3 shot groups with the right barrel, then shoot several 3 shot groups with the left barrel.

One of those barrels will be the lessor in accuracy, and that is the best your gun is going to shoot, so now you know what your target goal is..

Now you can shoot the gun right, left...If the two barrels POIs are far apart then you need to increase your powder charge, if they cross then you decrease your powder charge..Seldom will they cross over, but they can..get them as close as they will shoot and the group should be the same size as the worst barrel shot, thats the best your going to get.

Kudude

Yes, 10 of each at 50 and 100 yards.

Also shoot your 9,3x62 and its favorite load 10 each at 50 and 100 yards, using the exact same technique, ie no rear bag for the bolt rifle.

By keeping track of your left and right barrel shots as you shoot you will accomplish what Ray is telling you to do.

Why so many shots at each distance???

To eleminate as many "slightly" pulled shots as possible.

Trust me, just do it, let us see the results.

I don't think you can conclude anything about velocity and powder charge from your test. There is simply too much variation. I always weigh and load individual powder charges for my doubles and there is always a significant variation in velocity. If you are concerned about velocity, then you will have to average out 5 or 10 rounds. For my doubles I have never really worried about velocity. I load for the two barrels shooting close together at 50 yards, then at 100, and THEN, I check the velocity. That is not to say that I do not use the chronograph, I do, but I just document the numbers and draw no conclusions, unless I am over the recommended max. velocity (never happened yet)!
Just FWIW, Peter.

NE,
I'll do it, but if you have been observing Big Bore, I am also doing some work with the 458WM. I don't think I'll do both at the same time!!

Actually, when you shoot the 9.3x74 after the 458, it is like a stout shotgun load, even though that little Merkel only weighs in a 8 pounds. What a sweetie she is. Kudude