How much land engagement is too much?

[timspawn]

I am loading for a Ruger #1 30/30 using the Lyman 311041. The brass is trimmed to 2.027. The OAL is 2.528 which is just a touch long according to the Lyman Cast manual. My loaded round needs a small amount of thumb pressure to seat it in the chamber before I am able to close the action. I am getting slight land marks on my bullet. I don't think I can get a good picture of them. How much is too much? My load is 16 grains of 2400. Obviously my concern is an overpressure situation.

[Larry Gibson]

With that load and that minimal amount of land engagement any amount of pressure change will fall in the test string to test string variation.......in other words you won't see an effect from it with cast bullets. I have attempted to measure such variation (pressure testing with an Oehler M43 and a Contender Carbine in 30-30 with my own 311041) and could not with any certainty tell any difference.

You could trim the cases a bit more but if they chamber ok there should be no problem with them.

Larry Gibson

[dubber123]

I agree totally with Larry. Even if you had to press hard to seat them to the lands, what amount of pressure are we talking compared to the thousands of pounds a boolit/cartridge normally sees? I personally doubt even a max load would fall outside the range of normal enough to be considered a hazard. I prefer many of my loads to lightly engrave, especially on single shots. It provides a repeatable headspace, and I find they often shoot better.

[Wayne S]

"DITTO" to what Larry said, when I shot a T/C chambered in 30-30 I used a cut off 308 sizing die to neck size cases. the result with 30-30 cases and my 31141 [old mold #] that I could seat my bullets long, and when chambered, the nose would contact the riflings , and with the minimal neck tension the bullet would seat it's self into the case.

[Yodogsandman]

The Lyman #49 manual lists the overall length with the 311041 at 2.510". Why not seat a little deeper for a shorter O.A.L. to just enable the round to fit without using thumb pressure? So you have no interference to closing the action. The fit is so that closing the action, pushes the nose into the lands to barely engrave it. That's how I load my H&R 30-30 with the Lee 309-170F boolit.

[sthwestvictoria]

If you extract the unfired cartridge and the bullet stays put it is too much! Up to that I am happy to have quite a bit of engraving on the bullet, quite different to jacketed.

This is my 35 Whelen with a chamber cast and engraving on bullet. This amount of engraving still extracts easily:
http://i57.tinypic.com/106kpkz.jpg

I do not have a picture of my 30-30 (win 1894 pre-64) but it has no free-bore at all, rifling starting right at the case mouth.

[timspawn]

If you extract the unfired cartridge and the bullet stays put it is too much! Up to that I am happy to have quite a bit of engraving on the bullet, quite different to jacketed.

This is my 35 Whelen with a chamber cast and engraving on bullet. This amount of engraving still extracts easily:
http://i57.tinypic.com/106kpkz.jpg

I do not have a picture of my 30-30 (win 1894 pre-64) but it has no free-bore at all, rifling starting right at the case mouth.

This is very close to what I am getting.

[robroy]

Larry covered the safety concerns. sthwestvictoria covered the rest. If the boolit doesn't pull out when removing the loaded round from the chamber you're golden. I'm told the engagement helps support the boolit and start things off straight, assuming the round was loaded straight in the first place.

[Blammer]

too much is when you unload a live round from the chamber and the bullets stays there.

[williamwaco]

Larry and blammer +1

My personal experience is that I have never gotten best accuracy with the bullet touching the lands.
I load mine about .020 short of touching the lands.

This has nothing to do with pressure, it just gets me smaller groups.

[Blammer]

my best accuracy is when the bullet just kisses the lands.

[williamwaco]

my best accuracy is when the bullet just kisses the lands.

I have always heard that.

Some of the old timers even used the chamber as the seating die.

I have never been able to make it work

[nekshot]

Boy do I ever engage them too much! You pull one out of cartridge and get powder all over the chamber and action and you learn to keep barrel pointed up when extraction doesn't come as expected!! Nice little range rod sure can come in nice at a time as that!

[LAGS]

I noticed that in the pictures, there seems to be an absence of a crimp on the bullet.
From my experience, if you are loading for a 30/30 lever action and you roll crimp the bullets, if you have land engagement, the pressure seems to spike a bit at full bore loads.
I guess the crimp releasing and the bullet already stopped slightly on the lands is like a double whammie in holding the bullet from releasing easily.
When I experienced these spikes, I changed my loading, and did not crimp the bullet with the same load and same engraving. no more ocassional spikes or pressure signs.
But then I sometimes would get bullets pushing back in the casing slightly in the magazine tube under recoil if I did not have good a crimp.

[sthwestvictoria]

I noticed that in the pictures, there
.seems to be an absence of a crimp on the bullet.

I posted the pictures, not the OP and they are 35 whelen in a bolt rifle. I was really just demonstrating what a significant but safe engagement looks like. Apart from that I agree. Heavy crimp and engagement adds to starting pressure.