A Bit Surprised...

[BCB]

As we all know, changing a component can mean many different things when the hammer is dropped…

I finally got the Encore with an MGM barrel in 30-40 Krag shooting to quite good accuracy. This accuracy, or more correct, inaccuracy issue was discussed on another thread. But, I got that resolved (an interesting find and solution) so now I am able to detect changes in performance when components are changed…

I have been shooting the N.O.E. 311-202-RN and 49.0 grains of WC-872. Velocity is at 1953 fps. I had developed this load using Graf brass. Recently some of the Graf brass has begun getting split necks—not from lousy brass, but from being reloaded and fired at least 15 times (pressure is so low that I don't even us lube to size them) according to the number of boolits I have cast and what remains. So, I had some R-P brass that I had previously fired in the same barrel, about a dozen pieces, and I loaded them with the same recipe—all well and good until I went to the range…

I had the Graf rounds sighted in to be 2” HIGH at 150 yards. So, to begin using the R-P brass I fired a round at my 150 yard steel groundhog silhouette. It hit 2” to the RIGHT of P.O.A. So, I fired 2 more rounds and they all hit within about 1.25” group. I then fired 3 of the Graf rounds and they all hit within about the same 1.25” sized group, BUT 2” high as could be expected…

I was surprised at how much difference brands of brass make. I never saw such changes so distinctly in my entire shooting career that began in the mid-60’s…

Some numbers: The R-P brass will hold 52.9 grains of water with the N.O.E. boolit seated to the accepted O.C.L. The Graf brass holds only 49.2 grains of water with the boolit seated to the same O.C.L. Not much, but still the R-P has a greater capacity by 7.5%. Since QL indicates that only about 74% of the total charge was consumed during the firing of this round, I didn’t think that the extra space in the R-P brass would really matter—Seems it does matter…

The WC-872 is slightly compressed in the Graf brass, but not touched in the R-P brass. I wonder if this is what might be the difference—better ignition with the slightly compressed charge?...

Always something, but sometimes not a bad something--Just knowledge gained...

Good-luck…BCB

[waco]

Interesting. Do you ever anneal your brass? Neck tension could be playing a part???

[BCB]

Interesting. Do you ever anneal your brass? Neck tension could be playing a part???

I do from time to time, but not this stuff...

I want to start doing more annealing, but I have to find a temp stick or the temp paint. None locally though...

BCB

[Scharfschuetze]

I was surprised at how much difference brands of brass make. I never saw such changes so distinctly in my entire shooting career that began in the mid-60’s…

A good reason to segregate brass by headstamp. For my long range brass for match or accuracy shooting, I even weigh the brass and toss out the heavy and light cases. Weighing the cases will confirm your old statistics class studies on the bell curve and more importantly, reduce group sizes if your rifle is accurate enough to notice such things.


I want to start doing more annealing, but I have to find a temp stick or the temp paint. None locally though...

Once you do a few, you'll see the brass change color when it's time to water quench without a temp stick. I use an electric screwdriver with a socket head of the right size for the case. That keeps the case spinning and gives an even heat distribution. I do this with cases I have formed from parent cases after any major working of the brass. I also do it for ammo that gets crimped routinely. Generally a slow count to two while the case is spinning is enough heat.

[Larry Gibson]

Annealing will certainly add longevity to the case life by eliminating the split necks.

The greater capacity of the R-P cases will alter the ignition characteristics of the slow burning powder. It also will decrease the generated psi and thus the velocity as indicated by the lower poi.

[BCB]

Annealing will certainly add longevity to the case life by eliminating the split necks.

The greater capacity of the R-P cases will alter the ignition characteristics of the slow burning powder. It also will decrease the generated psi and thus the velocity as indicated by the lower poi.

That's what my thoughts were concerning the velocity. I might chronograph a few of the R-P cases and see how much the velocity might be lessened...

I wonder if I add a bit more WC-872 to get to the same velocity as the Graf cases if the impact points might become the same even with different brass?...

Thanks...BCB

[waco]

This is what I use. Money well spent.200819

[BCB]

A bit surprised again!!!

Chronographed the R-P cases to compare the fps to the Graf cases…

The R-P cases were right at 1853 fps using 3 rounds as an average…

That is ~100 fps less velocity than produced using the Graf brass. I never would have guessed it would have been that drastic of a change with just a 7.5% increase in volume of the R-P cases…

P.O.I. certainly would change with that amount of velocity difference…

Got 20 pieces of new Graf brass sized and tumbling now. The rifle is sighted-in using the Graf brass so I will stay with it. The first 20 pieces are all but depleted. I think I have 9 or 10 pieces that have not split in the neck area. But, the number of times they have been reloaded, I think one might expect the necks to start letting go…

Learn something every day…

By the way, Graf has 30-40 Krag brass in stock, at least they did yesterday when I ordered another 50 pieces. The brass seems to be pretty good quality. Just a heads-up for those who shoot the Krag but sometimes have trouble finding the brass…

https://www.grafs.com/retail/catalog/category/categoryId/764?

Thanks…BCB

[mdi]

What would happen if you adjusted the load for the Graf case to equal the velocity obtained from the R-P brass?

[W.R.Buchanan]

You might try just neck sizing your cases with a Lee Collet Neck Sizing Die. These dies don't work the necks hardly at all.

I use this die for Neck Sizing .303 British which is a very similar case to the .30-40. With the .303's the chambers are usually much larger (shoulder length) than the factory cases. Thus when you fire them the shoulder gets moved forward significantly. On my #4 Mk1 it moves the shoulder forward 1/16"! If you F/L Size them and push the shoulder back each time it just separates the case above the rim in 2-3 reloadings.

I have 7-8 on my PPU cases now for my jacketed bullet loads and they show no signs of coming apart. I attribute this to the Lee Die and good brass. My Winchester cases are relegated to Cast Boolit loads and they will last indefinitely.

Per Larry's recommendations a few years ago, I only neck size these cases and using the Lee Die cuts brass working to a minimum. So far I haven't even had to set the shoulders back but when I do I will only be pushing them back a few thou, and then starting over.

I would also recommend getting some Privi-Partisan Brass (PPU) as it is some of the best out there.

SGA Ammo in OK is a good place to buy the stuff. I just buy factory rounds and then I have good brass to reload.

Randy

[BCB]

What would happen if you adjusted the load for the Graf case to equal the velocity obtained from the R-P brass?

Or, I could go the other way too. I do have room in the R-P cases for more powder so I might be able to "fill" it with another grain or two of WC-872 to make it a compressed load and see what it chronographs like...

Thanks...BCB