How far out to seat a bullet

[Slooshark1]

I'm reloading for the 9.3 x 62 and I made up a dummy round tonight and blackened the tip to set it just off the rifling like you're supposed to. I seated the bullet (270 Grain Speer) out as far as I could and I still can't reach the rifling. I finally settled on seating it in the case mouth about 3/16". Is this okay to do or will the bullets come out under recoil? I tried cycling one in the magazine and it fits fine and feeds fine. The overall length measures 3.448".

Opinions and advice are welcome.

 

[BCBRAD]

I seat no less than one caliber, in your case, .366" as long as the round well load and eject loaded you should have no problem. this is what I do with my 35whelen, seat one caliber as long as you are where you want to be off the lands.

 

[Whelen B]

One calibre deep in the neck is a general rule of thumb. Some out of the box factory cases don't have even that long a neck - like the 300 Win Mag (.264" long neck for a .308" bullet). So it's a useful generalisation.

Worrying about seating near to the lands is for uber target shooters I think.

MANY of my loads are seated out long to get more powder in the case. If you are not needing and using the powder space then seating long is not buying you much in a hunting gun. Many guns with long throats like Weatherbys shoot accurately with bullets well back of the lands (approx. 1/2" freebore).

3/16" is not alot in the neck but can work of course. I'm thinking around 1/4" or a slight bit more as a minimum. Just my opinion.

Reliability of function is paramount when hunting so make sure your long loads feed well and will take abuse under recoil and handling. If you don't have a compressed load under the bullets or else some way to crimp them (factory crimp die), I think they may seat deeper under recoil battering. Just my opinion.

You asked = so all my 2 cents.

Waitin to hear how that CZ works for you. I bet the moose up west of Nipigon are shaking in their moose boots on account of that rifle.

 

[Andy]

With so little bullet in the neck, and not against the rifling you could also get into a hangfire situation. The primer sets off the powder, pressure builds up, then the bullet leaves the neck and pressure drops until the bullet engages the rifling and pressure builds up again. I agree that 1/4" is the minimum.

 

[JEC]

I like to seat a bullet so the shoulder of the boat-tail or bottom of a flat base is in contact with the neck to the point where the neck splays out to the shoulder. I believe that provides the optimum condition for concentricity which is one of the primary reasons for seating bullets close to the lands. I would try seating to this depth and compare accuracy to longer seated bullets. When seating to this depth, get a feel for when the bullet is about halfway down the neck, then turn the cartridge 1/2 turn and finish the seat. The theory here is that turning the case will result in some "straightening" if the seater is pushing the bullet to one side. In the end, accuracy depends highly on the bullet being perfectly centered.
The distance a bullet is seated from the lands also affects the time of "peak" pressure. You have to play with seating depth for your particular rifle and bullet combination.

 

[Noel]

I just checked my data from my Brno loads and the longest I tried was 3.440" but went back to 3.400". The throat was real long and the mag had plenty of space, I think it just fed better when slightly shorter(?)

Keep in mind it is not the same case but my 9,3x57 I seated long dummy rounds in an effort to try and get them to jam but they always went real slick. Neck engagement IIRC was about 3/16" and I never had any trouble.
With saying that I will be the first to admit if Andy suggests otherwise, I'd go with his final word not mine. He has much more experience than me, I just wanted to share that in this one case I did have success.

 

[gitrdun]

With so little bullet in the neck, and not against the rifling you could also get into a hangfire situation. The primer sets off the powder, pressure builds up, then the bullet leaves the neck and pressure drops until the bullet engages the rifling and pressure builds up again. I agree that 1/4" is the minimum.

That makes a lot of sense. Man, the awesome things that one learns when just casually reading threads.

Andy, do you think that a factory crimping die might also be useful in this case, just to add a bit more neck tension?

 

[Andy]

Andy, do you think that a factory crimping die might also be useful in this case, just to add a bit more neck tension?

I wouldn't do it for that reason.

If you have at least 1/4" of bullet surface in contact with a properly tensionned, clean, dry neck, you should be fine. 2-3 thou of neck tension (difference between bullet diameter and sized inside neck diameter) should do it. You can increase neck tension by using a slight smaller expander rod, or with a neck sizing die by adjusting it tighter.

I only have experience crimping cast bullets. With jacketed, for my tube mags, I prefer to use a powder that fills the case to prevent it from being pushed in, and the heavy recoiler (458 WM) gets the bullet seated to the crimp groove and no problems to date. The funny thing with crimp dies is that when they create the crimp, some actually lift a bit of neck away from the bullet just behind the crimp. The mechanical joint prevents the bullet from falling out or being pushed in, but I'm not sure if it would do what we want here.