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Post by rangeball on Mar 18, 2009 16:06:16 GMT -5
Douglas told me their .50 barrels they sell SMI have a land and groove spec of .510/.500. In a recent thread onecardchuck measured his savage .50 at .503/.499 (if I remember right). That .004 difference on the seems considerably more shallow than the douglas .01.
Is the deeper rifling of the douglas any advantage? A disadvantage?
It would seem that with adequate pressure it would get a better bite on the bullet or sabot and possibly be more stable/accurate, but I don't know.
Maybe this is the reason they say they can load .458 bullets in the regular non-CR short black harvesters.
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Post by jims on Mar 18, 2009 16:43:38 GMT -5
I cannot speak for what those barrel specs are but when I was looking at barrels generally I found the land/groove difference to be in the .007 to .009 range.
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Post by dave d. on Mar 18, 2009 16:50:44 GMT -5
:)range more knowledgeable people will give you a better answer but i would think that a shallow groove would be eaiser on sabots and better for sabotless obtrurate.sealing would probably be better also.
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Post by Dave W on Mar 18, 2009 19:09:21 GMT -5
:)range more knowledgeable people will give you a better answer but i would think that a shallow groove would be eaiser on sabots and better for sabotless obtrurate.sealing would probably be better also. I have always wondered if this is why my .457 barrel shoots sabotless so well but the Pac Nors .450/.458 seen to shoot better saboted loads. I don't know the answer Range but I would think a deep groove would be harder on the sabot base since the base has to flair more to get a seal. |
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Post by whyohe on Mar 18, 2009 19:41:08 GMT -5
ok here is my UNPROFESIONAL opinion. for sabotless shooting the shallower would be better as said for sealing. i think just a bullet is still a bit stiff to fully seal on deep rifling. now with a sabot since it is plastic and more plyable the deeper might work better cause you would get a better grip on the sabot. but again if too deep you still might get a poor seal.
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Post by rangeball on Mar 19, 2009 8:32:17 GMT -5
Sealing, hadn't even thought of that...  I do plan to try the thor and hornady's sabotless, guess a ww or two may be needed if it is indeed as deep as they say, but their barrels are supposed to shoot in cartridge rifles, so maybe not. Guess I better order some just in case. May make shoving a .50 bullet down the barrel easier though, hopefully. I'm convinced now more than ever that that's why they like the short black NCR harvester and a fatter bullet, plenty of material to fill the grooves up. |
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Post by sw on Mar 20, 2009 14:52:03 GMT -5
Years ago, when most MLers were roundball only: I'm refering to replica guns(Lyman Planes Rifle, Green River Barrel Company, Douglas ML barrels,etc); most MLing barrels had lands of .009"-.011". Then the conical shooters along with 48 twist barrels vs the 66-72 twists for RBs and they had normally 0.0045" deep lanfs(Thompson Center Hawkin, etc). A conical trying to obturate into 6-8 0.011" deep lands would have a problem, IMO. I think most of our barrels are between 0.0035-0.0045" now. This seems about ideal AND the twists are better also: 48 twist was about good for nothing.
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Post by rangeball on Mar 23, 2009 15:13:45 GMT -5
I just measured a .458 barnes in the black harvester regular- .510.
Seems like I need to concentrate on .458s, unless it's possible to knurl .451-2s up that much?
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