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Chamber variance in my 40-50 SS (Read 2834 times)

Vic Ex Member	Chamber variance in my 40-50 SS Sep 17^th, 2005 at 9:45pm	Print Post
	Hello. I've got a Cody Ballard 40-50 SS that I'm in the middle of working up a good load. It's a bit unpredictable... some 2" groups, lots of 3-5" groups at 100 yards. Not consistent, even with the same loads. While doing some reloading for it, and testing a round for chambering, I noticed that the rifling was engaged .050 on one side of the bullet, and not visible on the other side. When chambering bullets with deeper seating, I noticed that the rifling on the "off" side was uneven, and set back .050-.060 from the rifling on the other side of the bullet. I'm not sure if this is a sign that something is a bit off in the chamber, or if this is considered normal. Your advice is appreciated. Thanks. Vic


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JDSteele Ex Member	Re: Chamber variance in my 40-50 SS Reply #1 - Sep 17^th, 2005 at 9:49pm	Print Post
	You should do a chamber cast ASAP, it's the only way to find out exactly what you have. What you're describing is NOT normal IME. Good luck, Joe


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singelshotman Ex Member	Re: Chamber variance in my 40-50 SS Reply #2 - Sep 18^th, 2005 at 12:11am	Print Post
	i'm sorry, but your chamber IS OFF CENTER, due to an unsize pilot on the chambering reamer-from what i have read, this problem seems to be unique to .40cal barrels(two different bore sizes in use).The only way to fix it is to set the barrel back and rechamber using the right pilot this time.I'm sorry you used an incompentant gunsmith.


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Vic Ex Member	Re: Chamber variance in my 40-50 SS Reply #3 - Sep 23^rd, 2005 at 9:16pm	Print Post
	I think I also need to consider "brass variance"... I talked with Glenn Fewless about this issue (I mailed my Sharps barrel off to him to install scope blocks) and he suggested I look into brass issues, specifically the thickness of the brass as you get closer to the case head, given how short the 40-50 SS is, and how deeply seated the bullets are in those blown out 30-40 Krag cases. In reloading a new batch, I noticed that the bullets are a slip fit for the first .300 inch into the case, then it suddenly gets very tight, to the degree I think it is swaging the base of the bullets a bit. I can definitely feel a "2-step" when seating the bullets... effortless for the first .300, then you hit a step and it starts to take a good bit of pressure to seat the bullet the last .300 inch, and that is not due to compressing the black powder. I annealed the cases, and that helped some. I test chambered a bunch of new loads, and now some of them come out with even rifling engraving all around. But most are still not perfectly concentric. I use a Meacham inline seater, so I don't think it is my reloading technique. I'm leaning now on the assumption that the variations are caused by variations in the case thickness, especially since I can feel distinct variations when seating the bullets.... some are a lot tighter than others, and these are all fire-formed cases with no sizing. The annealing helped, and today I shot my best groups yet... nothing competitive, but under 2" at 100 yards for the first time, and the dispersion is much more even and I'm now seeing some consistency in the patterns. I don't think you can "neck turn" brass down for a length of .600 inch, so I'm not sure of the solution, short of ordering cases from Rocky Mountain Cartridge based on a chamber cast. Maybe I'll try a sample of Rocky Mountain cases and see how that goes, and continue fiddling with my current bunch of cases. Thanks Glenn for the good advice, and I'll attempt a chamber cast to verify that issue. Vic
	« Last Edit: Sep 23^rd, 2005 at 9:25pm by »

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JDSteele Ex Member	Re: Chamber variance in my 40-50 SS Reply #4 - Sep 24^th, 2005 at 10:33pm	Print Post
	I don't see why you couldn't neck-turn your brass down to the .600" mark, if you do it in the right way. If it was my problem, I'd first make up a steel mandrel to expand the inside of my case necks down below the seating depth, so the inside of the case walls would be parallel with each other. Might take a few resizings to get everything parallel inside, but that would be my goal. Then turn the outside to the desired dimension, using the mandrel to support the inside of the necks as usual. Again, might take a little fiddling to get everything squared away but you should be able to end up with parallel case walls. Then just fair the necks into the bodies with the neck-turning tool & polish everything. Of course a final annealing will help matters tremendously. Sounds like a lotta work to me, but it oughta end up OK. Good luck, Joe


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