Cast bullet seating.

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  • Last Post 23 September 2008
mosinutty posted this 15 April 2008

I read somewhere that to achieve the best accuracy with cast bullets the overall length should be long enough so that the bullet tip kisses the rifling in the bore. Has anyone heard of this? I'm loading for a M91/30 mosin and I don't see anyway possible to achieve this with the bullet length I'm casting. I'm curious if this is even possible with this firearm, and that it may only be obtainable in some rifles.

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R. Dupraz posted this 15 April 2008

Yes, the cast bullet kissing the rifling is usually the place to start. However this in not a hard and fast rule. Some rifles don't like the nose of the bullet there and I have a 98 Mauser with the Star of David on the receiver ring that is one of them.  Don't know much about the M 91/30 so's can't help you there.

RD

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billwnr posted this 15 April 2008

The load I shoot in my rifle shoots best backed off about 0.20"

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RicinYakima posted this 16 April 2008

My Finn 28/30 likes the first driving band pushed up snuggly in the throat, but doesn't seem to care it the nose is touching the lands or not. Ric

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mosinutty posted this 16 April 2008

What methods are available for determining exact chamber length?

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giorgio de galleani posted this 16 April 2008

To get chamber measurements,you can measure a chamber and bore cast using cerrosafe,a low temperature casting alloy sold by Brownells. This work I'll do to morrow in one of my three(presently) SMLE rifles.Then I 'll send the cast to Veral Smith of LBT and ask him to make a four cavity mold with base band that fit the throat and a nose engraved by the lands.

My  enfields have a long or worn throat,a member from the NZ calls  it “cordite throat",that resembles the throat of a couple of Moisins I owned.

I had a discussion on this subject a few weeks ago and had some good advice from Ed Harris and other members,on making do with a short 313 bullet and designing a longer heavier one.

I have NEI bullet #72 ,designed for the 7.62x39 SKS that shoots wery well seated  well inside the neck,in a two groove N°4 ,a 7.62 x54 Dragunova and decently in two other 5  grooves enfields.and inthe Moisins that I traded down south in Tuscany some times ago .I 'll get a 44 mag  Marlin lever gun.

I presume that for filling the throats and engraving the nose into the lands we need a design different from Lyman 314299,as this design is made for feeding in any chamber,feed faultlessly and blast away ,as  a machine gun ( the mad minute) at short range.

The amount of work ,skulldudgery and money you spend,  depends on what kind  of accuracy you expect or need from your gun and sights. I witnessed  on aTV screen a fellow at Alessandria range hitting regularily an eight inch target at 300 meters with a N°4 rifle T with original scope using sierra 311 bullets ,I would like to get 75% of that accuracy with one of my rifles and cast bullets.  A Scoped Moisin can shoot too,so,good luck to you.

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cityboy posted this 16 April 2008

mosinutty wrote: What methods are available for determining exact chamber length?

If you mean the distance from the bolt face to the end of the neck, get a Sinclair chamber length. The are inexpensive and easy to use.

Jim

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mosinutty posted this 16 April 2008

ok, That gives me a direction to go in. Thanks guys!

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hyoder posted this 17 April 2008

In your original post you said the “tip' of the bullet.

With a typical rifle bullet you should have a bullet with a nose of some length that is smaller than the front driving band. The front driving band is what should just barely contact the lands or be set back just a little. With this type bullet, the nose, in the case of a bore riding bullet, should only barely contact the lands, otherwise not at all.

In the case of a tapered bullet, the bullet will contact the lands at some point along the body of the bullet.

I wouldn't think that in either case the “tip” should not contact the lands. 

If we are talking about a short fat pistol bullet you might get close.

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sniper posted this 02 May 2008

Try this:    Make several cuts (2-4) in the neck of a sized brass case, extending them into the shoulder area.  This lessens the neck tension for what will come next, but alows the brass to grip the bullet securely. 

Then slide a bullet of the type you will be loading into the case, leaving it long. Oil the bullet to eliminate sticking, and gently chamber and exrtract the round.  

Check it for any pulling by the rifling/throat, and measure, using the Sinclair International comparator ($18.50 + shipping) and a caliper,  as was mentinoned in a previous post.   LOTS simpler than the Stoney Creek comparator, and fewer parts to contend with.  

If your bullet of choice will reach the rifling, do this several times, to get an average.  Ths will give you the length of cartridge, with the bullet just touching the rifling, or close enough for all practical purposes.  

Adjust from there, as your rifle tells you what it likes best. :)   Eschew further ballistick proctology, and go shooting!

This should reduce the “work and skullduggery", not to mention Thaumaturgy necessary (Repeat softly three times...voodoo, voodoo, voodoo.  No chickens were harmed during the ceremony...really, they weren't!:cool:)  to obtain THE load for your rifle. But only if you write the results down. (Don't ask how I know this!)

Do I even have to say: Keep the case for future measurments, and DON'T try to load it?

 

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mosinutty posted this 03 May 2008

voodoo........voodoo........voodoo. I feel better now, Thanks Sniper!;)

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lordgroom posted this 10 May 2008

How about breech seating?  Placing a bullet into a case and chambering the round which drives the bullet into the rifling.  The  just back off .001 or .002. 

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mosinutty posted this 15 May 2008

I've attempted breach seating but do not have enough length to touch the rifiling.

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billwnr posted this 15 May 2008

you didn't say which bullet you are loading.   Have you tried longer (and heavier) bullets, possibly ones with thicker noses too?

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hunterspistol posted this 18 May 2008

:coffee My info has been from .05” to .20” from the rifling, if you can get the exact breach seating length.

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oake posted this 18 May 2008

Sniper if that one isn't in the book, it should be

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lordgroom posted this 21 September 2008

I have heard to seat back .002 from the bullet touching the lands and someone I respect just told me to drive the bullet into the lands .002 and work from there.  He even said some bullets need to be driven further into the lands.  Which is correct?

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hunterspistol posted this 22 September 2008

:coffee  From what I understand, and I'm no expert here, driving the bullet into the lands would be done with a reduced powder load-since it may create more pressure.  Then again, I shoot pistols so, stick with the rifle shooters on the Nagant. They'd know more about it than myself.

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RicinYakima posted this 23 September 2008

It depends upon what you are trying to do. For benchrest competition, I seat them so that the camming of closing the bolt  pushes the bullet 0.030 into the seat. Then you can't take the case out with out leaving the bullet. That is a bad idea for a field round when you want to be able to remove the cartridge. Ric

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