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32-40 Accuracy
glabray
Member Posts: 679 ✭✭✭✭
I've just started loading for a pair of 100-year old 32-40s. I began with the 170gr Lazer-Cast bullet and 25gr of 3031 in new Winchester brass. Although the bores of both guns are very good, accuracy was terrible with both. A few bullet holes showed signs of slight keyholing. Due to the age of the guns, I don't want to heat things up too much. However, has anybody ever had any luck increasing the velocity of a long bullet in order to get a higher RPM and more stability?
Comments
Mabey try a heavier or lighter bullet
Tim
That's one of the problems with theories, they aren't always correct.
There are occasions when stability is enhanced by the addition of more velocity. Your load is a bit low and think you could stand to run it up the scale a bit.
I also think that these Lazer Cast bullets are maybe a bit too hard for the barrels that you are using. These older barrels might be better suited to slightly softer bullets.
The bullets also are supposed to be coated with something that makes them slippery. This is an indicator that more powder is usually required to get the velocity up to where it would be when compared to non-coated bullets. This is similar to Moly coating.
Best.
Try something like 12-14 grains of 4227. I had good shooting out of the Laser Cast 170 gr .30 bullet with 14 grains IMR4227 in .30-30. If you have some 2400, make that 11-13 grains.
The other possibility is that they are undersize in which case there is very little you can do to make them shoot. Laser Cast says .322". Have you slugged your barrels? What make are your rifles?
Hey, nononsense, tell me about this coating to make them more slippery. All the Laser Cast bullets I have seen were conventional wax lubed lead. I tried some coated cast Precision bullets in a rifle once and they did not shoot accurately. Makes good pistol bullets, though.
Hey, Hawk Carse, I mis-stated, it's the "Slick Silver Bearing Alloy" as noted in their advertising.
From the Laser-Cast website:
No leading
Slick Silver Bearing Alloy yields highest velocities of all Extreme accuracy.
Generally when something slippery is a part of a load combination, it requires more velocity to get the same performance as from those bullets that don't have some sort slippery preparation. We all found this with both Moly coating and the Barnes coating. Hence the problem with achieving accuracy with the Precision bullets that do have a coating. You have to work with the loads more to get the best accuracy and an accurate load usually needs more velocity.
The loads that you suggest are not only 1/2 case capacity but also 1/2 of the SAAMI pressure rating. At least the load that was originally posted was closer. Yes, there are such things as slower nodes that demonstrate accuracy but if the poster isn't seeing stability at the velocity he's loading now, he most likely isn't going to see any better stability at a lower velocity.
Maybe what he really needs is a new crown. It could be that the bore needs a good scrubbing. It could be that the bore is not in the best of shape as suggested. A good borescope might pinpoint the real problem or it still might be the loads. There are dozens of possibilities that could be the problem or be contributing to the problem. This is all guessing anyway since an absolute fix will only come from more work and tests.
Best.
And if he should happen to have an original Ballard rifle, half of SAAMI maximum is about what it is good for.
I don't think you can apply normal target rifle loading procedures to bulk commercial cast bullets out of pistol alloy with pistol hard wax lube and pistol level QC. I, for one, have to load them light to get any accuracy at all. Handcast bullets out of linotype or quenched arsenical lead are a different matter and you can push them harder and usually more accurately. But I find bullet casting and meticulous inspection real drudgery, which I apply to .38-55 for my Winchester Single Shot, and nothing else.
As far as the rifles go, we have no real information on bore condition or dimensions. If a cast bullet doesn't fill the grooves, it isn't going to do much with smokeless powder.
You don't state anything definitive about the rifles so we don't know if they are collectible or valued as collectible. This can make a difference as to what you can or cannot do to achieve accuracy.
Sometimes if we start with a logical series of steps examining the entire rifle first and making any corrections needed (or allowed), then examining the shooting style and finally working on load development, we can potentially solve the problem of inaccuracy.
I suggest cleaning the barrel carefully but thoroughly then getting a good look at the inside with a borescope. Make sure that you also spend some time examining the crown as well. However, if there is a good deal of value to these rifles then it might be a problem to correct a deficiency with the crown without affecting the value. Only you can make that call.
Slugging the inside of the barrel is always a good method to use to find out the size and shape the inside of the barrel. Not only will you be able to find out the dimensions of the bore and groove but you can also feel tight and loose spots if you slug the entire length. This can take take several attempts.
How are you holding the rifles to test these loads? Are you resting the forearm on bags, the barrel on bags? You see where this is going. There are a number of things to look at insofar as how the rifle the held and fired. Maybe your shooting style with this rifle requires changes to achieve better accuracy.
For load development, deriving the dimensions from slugging will help you find and select the proper bullets to use for testing. There are several powders that are appropriate to this cartridge that are both safe and have the potential for accuracy. The problem is that you have to research written data or use anecdotal information as a place to start. Both can have drawbacks and inaccuracies so using a combination of both can help build a good picture of the powders and bullets that can be used for a starting point.
There is lots more but this should get you going in the right direction. Post more as you progress.
Best of luck!