45-70 Help Needed

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Texas Colt

May 30, 2005
Central Texas
I have a question about reloading for the 45-70. I am an experienced reloader, but I can't figure out why I am getting such wide spreads in velocity. The gun is a Browning Saddle Ring Carbine with a 22" barrel.

For example, I shot a test load today that was 44.7 grains of Reloder 7 over a 300 grain Speer JHP. OAL is 2.540. Powder for each round was weighed individually. Here are the results of four shots...


As you can see there was a 181 fps variance. WHY? I have gotten similarly erratic results using IMR 3031 powder.

Any thoughts???
inconsistent seating, flash holes, diff. brass mfr/age, old powder, or inconsistent crimp?

If none of the above try a different type of powder.
Some variation is normal, but you might try a stiffer crimp, if you haven't done so. The problem is the case walls are so thin on the .45-70, you have to be careful not to crumple them.

I'm taking my 1895 Marlin .45-70 on a moose hunt in Northern Alberta the end of this month. It's my first moose hunt, and probably the only one I'll be able to do before I die. Ask me if I'm excited!!!

Okay, here's some additional info...

Winchester brass, Hornady dies. Each completed round was also measured to insure correct OAL.

I use the same processes for several other calibers (38-55, 32 Win Spcl, 308, etc) and have not had such erratic results.
Inspect the brass for any differences in flash holes, also different batches of brass can carry different web contours (even same manufacture). The contour differences are usually revealed by weighing brass.

How you clean your brass can affect consistency also, burnt powder can flake off the case while sizing and settle near the flash hole, then get pushed into it by the charge.

You will have to track it down yourself, though powder quality is probable if the brass was processed well.
4 shots is not a very good experiment. There simply aren't enough shots to really analyze. Sure the numbers don't show much consistency, but the lows/highs might have been a fluke, or might have been misread by your chrony.

Load up some more and fire them over your chronograph. Check your chronograph with a factory load of some type as they usually have surprisingly low ES's and SD's. Shoot a .22lr and then a centerfire rifle of some sort to verify. Your batteries might be low, and chronographs do strange things as the batteries begin to fade.
Tex, it seems the advise might be moving in the non-productive direction. The Saddle Ring carbine is not a benchrest gun, the primer hole uniformity cannot explain the erratic velocity.

Perhaps the bullet is the culprit, I always had better results with 400-405gr bullets in my 45-70 High Wall. Reloader 7 and IMR3031 are both good powders for this application, no issue there.

Have you had better results with other loads?
Is this a new gun? Any mechanical issues?
You are at least 6 grains below max on the RL7. In working up loads in the higher volume cases, I found they were irratic at lower loads. As the loads approached max, they performed with greater consistency and accuracy.
Thanks for all the input guys.

LT, the gun is new. I had consistent results with some factory Winchester 300 grain ammo. I do have some 400 grain bullets I can try, but I was hoping for success with the 300 grain bullet simply for reduced recoil.

I'll just have to diligently load up some more and do more testing. It's a good excuse to shoot more, right?
Another question... I have heard of using Cream of Wheat as a filler for reduced black powder loads. Will that work for smokeless powder as well?
Cream of wheat or corn meal can be used to fill the unused case space, but there are commercial products that work better. Puff-lon comes to mind, I know some cowboy match folks that use it. There are others, like Dacron cotton-ball-like stuff. I have no personal experience with those, so I will defer to those who used it.
Using a filler introduces a variable into the equation that has some seriously negative consequences, namely a blown up gun. If I couldn't get a gun to shoot I would trade it away before sticking breakfast cereal into the case. YMMV, but that is my opinion on the matter. The Lyman manual has a lot of info using fillers, and if you must, consult the 47th or 48th.

People have been shooting 45-70 with smokeless for a long time without filler and produce spectacular results. IMR 3031 is a fine powder for this cartridge, as are many others. That is one of the great things about the ol' girl, she shoots almost anything well.

I don't see how the bullet could produce such erratic velocities unless they were really BAD bullets. I don't think primer hole uniformity is the answer either, but I think it would have much more impact on consistent velocity than the bullets.

But whatever you do, please don't use a filler. It simply isn't necessary. Again, how was your accuracy?
Had much the same problem with low velocity smokeless loads out of my 86 Winchester.

First, the recommendations your getting regarding a filler is dead on. With most smokeless loads in that case, you get a lot of dead space. As soon as you move the case from verticle to horizontal, the powder spreads out along the bottom side and leaves the upper portion empty. The result is inconsistent ignition.

Second, if you are not already doing so, try magnum primers, the hotter the better. I experienced the inconsistent velocities, but also ran into problems where the cartridge would either hang-fire, or not fire at all with standard primers.

With the falure to fire, the primer would pop, create just enough pressure to drive the bullet far enough into the barrel that it would have to be driven out with a dowel rod. When you ejected the round, it dumped dirty discolored powder all over the inside of the action.

The hang-fires were down right dangerous. The primer would pop, you would wait a few seconds and about the time you were starting to lower the gun it would go off. Not a pleasant experience!
I use IMR 3031 for my .45-70 loads, but I'm shooting 405 grain bullets. Another good powder in this caliber is IMR 4895.

As for case fillers, I have quite a bit of experience with them, but I use Super Grex. The only rifle caliber I use it in is my .45-120, with smokeless powder. In this case, IMR 4895. If you don't know what you're doing with case fillers, you stand a chance of ringing your chamber and ruining the barrel. I've found that the .45-70 doesn't require the use of fillers with any of the loads listed in the manuals.

For a lighter load, I get excellent accuracy with Berry's 350 grain plated bullet, which is made specifically for the .45-70. I drive it pretty fast with IMR 3031 and it really shoots well from my 1895 Marlin.

Hope this helps.

Holy cats, that's a huge spread. 44.7 grains of RX-7 should pretty much fill the case. At least full enough that you don't need or want a filler.

Yesterday, I was shooting my buffalo classic H&R. I was shooting 405 grain lead boolits,(lee 405 hollow base), with H-322 under them. The load in the Lyman 48th called for 43.0 to 46.5, with the 46.5 being a compressed load. Even the 43.0 was at least 90% load density. Here's the chronograph readings for the four loads I shot.
Av.1753 ES 13.3
av 1798 ES 50.7
Av 1841 ES 37.2
Av 1882 ES 25.8

The groups were getting wider with more fliers as the powder charges increased. So I didn't fire the 46.5 loads,(another reason was I was getting beat up by the steel butt plate, even with a past magnum pad on).

So you can see there's some variation in the extreme spreads. None of these were real bad for that big of a case. I think the reason I was getting worse groups was I was exceeding the strength of the alloy I was using. I need to make some with harder alloy.
TKendrick and Shoney were onto the real problem.
You're not getting consisitent ignition. I've seen this with my .45/70 loading through the years. It's due to the "empty space" with light charges of smokeless powders.

With your action, you can go to the level II loads (1895 Marlins, ect.).
I've seen lack of consistency with IMR/H4198 and even faster powders (such as 4227 and #2400) at the level I loadings (trapdoor action, ect).

With fuller cases (ie; over 39.0gr of 4198), and essentially full cases of 4895, Varget,3031, 4064, RL15, ect. you'll get nice low SD's. Ditto Black Powder and replica's which are loaded to compressed load level's.

My personal favoite load with a 300gr bullet is a RCBS 300gr FNGC (318gr w/SPG and gascheck) over 53.0gr of IMR3031 or 45.0gr of 4198. These produce about 1850-1900fps from my GuideGun and near MOA accuracy.

With Black powder and replica powders, a magnum primer will help, but is not necessary.

If you decide on a "filler", my recommendation is to use dacron pillow stuffing. It's the same thing that the powder manufacturers use as a binder (see Alliant's powders labels.....). It also is consumed in the combustion process and hence is much less likely to cause bore obstructions or over-pressure issues.
you might also want to try magnum primers,

the first 25 rnds I loaded for my 1895CB was with data68, std CCI primers under a 405LFP had a few kernnels/balls of unburned powder left in the bore,

I loaded the next batch using the CCI34s and was getting a complete burn and as a plus the groups tightened up a bit.
Sounds like I'll give one of these fillers a try. Since I've already got the velocity where I want it, I don't see the point in increasing the powder charge just to gain consistency. 1800 fps is plenty of power for Texas whitetails and hogs.
I really think that is a variable you do NOT want to add to the equation.

With almost 45 grains of powder, your load density should be such that it simply isn't necessary. Heck, even with a pistol powder, a filler is just not needed.
Are you hand tightening your dies ? I do and then give them a extra snug with a adjustable wrench :) It's a funny thing getting older, I don't have the grip of my youth and sometimes I don't consider the implications.
When using a case filler, you have to work up your loads from the beginning with the filler. You can't just add filler to an existing load. Case fillers reduce the volume of the case and change the burning characteristics of the powder. I use them for some loads, but not in the .45-70, as I've not found them necessary.

Hope this helps.

With almost 45 grains of powder, your load density should be such that it simply isn't necessary. Heck, even with a pistol powder, a filler is just not needed.

I agree 100%. I just went back to the loading room. I put 44.7 grains of RX-7 in a R_P 45/70 case. Then using a rem 300 JHP, I figured out that there's a .300 empty space between where the powder ends and bottom of a seated 300 rem JHP.(Measuring from the bottom of the bullet to the center of the cannelure, then measuring to the top of where the powder ends, then subtracting the difference).

That's not much empty space. Not enough to be the cause of the extreme spreads. The theory says that if the powder is NOT directly on top of the primer flash hole, the primer flash may spread out over the powder laying on the side of the case, igniting it differently each time.

In order for that to happen, the load density would have to be 50% or less. Or the barrel would have to be pointed in a down angle, like shooting down hill.

I would certainly try that load again. Possibly it was a fluke.

Winchester brass, Hornady dies. Each completed round was also measured to insure correct OAL.

?, were all the winchester brass the same age?
Snuffy, thanks for taking the time to figure that out. Sounds like I don't need a filler after all. I haven't had time to get back to my reloading bench, so I really appreciate your research.

My Winchester brass is all once-fired and from the same lot. I guess the other thing I need to look at is case length to make sure I am getting a consistent crimp.

I'll need to find some time to load another batch and try it again.
Kids, we are trained professionals...yeah right...don't try this at home.

Try AA2015. I use it in my Buffalo Classic.
I've gone low, down to 46gr and a 405gr JSP bullet.

High up to 53gr Speer 350gr bullet.

Poweder works great with no suprises or erratic chrono readings.

I think your problem is with your crimp; inconsistent velocities like you are seeing are usually the result of inconsistent burning of the powder. With the light for caliber bullet you are using I think that you need a better crimp to hold onto the bullet to let the pressure rise faster and give a better burn of the powder. Can you spin the bullet in the case before you crimp (i.e. the neck has been expanded too much) or can you spin it after you have crimped (i.e. you are over-crimping the case, causing the neck to be expanded away from the bullet)? The tension of the case neck does most of the work of holding onto the bullet, the crimp is just to add a little mechanical lock to help prevent bullet movement. An inconsistent crimp will give you an inconsistent burn and result in inconsistent velocities.
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