loooong seating

T

tpende

Guest
if i seat my bullets to the lands it only leaves about a .100 of the bullet in the neck of the case. is this too little? i know that the deeper into the neck i go the more centered the bullet will be, but if its pushed up against the rifling does it matter?
 
I'm in the same boat as well. Am working up loads for a custom 6br using barts ultras. I have .050 freebore and am only having about .100 of bullet in the neck too. Barts "originals" will go into the neck further which is my next step. But I'll second Georges question, who else makes 68gr bullets a bit longer with about .2435 o.d. ?
I don't mean to open a can of worms but on 6mmbr.com, under the bullet reviews for ultras, they state .050 f.b. is what you need (??) chris
 
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Fowler Too Long????

Historically, the 7 1/2 ogive Fowler has been an example of a bullet that has about the shortest set-up as any bullet available. You must have a throat length, (freebore), in the .090 range for a Fowler to stick out that far.

A Barts Ultra is a different story. It is a typical double radius ogive bullet needing a much shorter freebore so as to have an adequate amount of bullet shank in the neck

I disagree with your analogy that a deeper seated bullet will make a straighter round. A straight round is just that, and is a product of other factors, such as case consistancy and die quality, not how much bullet is in the neck.........jackie
 
Jackie, so .100 of bullet in the neck is ok as long as it shoots?
 
Another Point

When I went to a "zero" freebore, many shooters asked why. The main reason was to get the overall powder capacity of the chambered round back to where it should be when using the 00 Bruno Boat Tail.. By this, I define the overall capacity as the distance from the bolt face to the point of first resistense, that being that point where the bullet touches the lands.

This gets the pressure spike back where it should be. Hear is an example. When I was shooting a .050 freebore, I would get an average 3390 to 3410 fps from my pet load. Just going to the zero, and getting that pressure spike back toward the chamber, the velocity picked up almost 50 fps. That allowed me to lower the charge just a tad, and get the agging capability exactly where I wanted it, but with better, (I think), consistancy.........jackie
 
tpende, just to give you an idea of how different bullets vary the seating depth;
These are all 6mm 0.825" jacket based bullets. The numbers below are the bearing length of each bullet.

66g Fowler =0.360"
65 Berger= 0.315"
66 Knight/7 ogive=0.362"
68 Barts Wedge=0.285"

Most 7, 7.5, 8 ogive noses, like the Fowler, Arnette, Knight, etc. are going to be in the 0.360" range.

Some 6PPC reamers have as much as 0.085" freebore which gets you close to a 0.100" seating depth. But the 0.100" depth range you get should shoot fine as long as you get the jam and powder in the right amounts.

You will probably never be able to shoot a boat tail in that chamber while staying in the 65-68 grain bullet range. You could go to something like an 80g Berger which has 0.425" bearing, but that bullet is a bit much for 100/200 benchrest.
 
i wish it was a 6mm but its a .223. i have to shoot 50-55 grain bullets
 
Well duh!!! What do you expect from a factory chamber. I was beginning to suspect it was something like this or a 6BR or 6XXX chambered for long heavy bullets. I have one 223 that you cannot even reach the lands with a 55 grain bullet pushed into the chamber by the case. Course it is a plinking rifle, NEF handi rifle. Most BR guns are chambered with tight chambers. If you want to reach the lands with the 223 you may have to order a different reamer than what the factory uses. Hope this helps.
Donald
 
JerrySharrett said:
Some 6PPC reamers have as much as 0.085" freebore which gets you close to a 0.100" seating depth. But the 0.100" depth range you get should shoot fine as long as you get the jam and powder in the right amounts.
Click to expand...
Jerry, all this assumes a 1.5-degree half-cone angle. I have a 2-degree half-cone angle reamer that Jeff Summers helped me with; it is close to one of his old ones.

I can shot the 67-grain BIBs on a .790 Jacket. I can even shoot the old Fowler 63-grain bullets on the .760 jacket, but not much of the bullet is in the neck. Freebore on this one? .090
 
Charles E said:
Jerry, all this assumes a 1.5-degree half-cone angle. I have a 2-degree half-cone angle reamer that Jeff Summers helped me with; it is close to one of his old ones.

I can shot the 67-grain BIBs on a .790 Jacket. I can even shoot the old Fowler 63-grain bullets on the .760 jacket, but not much of the bullet is in the neck. Freebore on this one? .090
Click to expand...
Charles, my 6-40 PPC has an 0.085" freebore and I can shoot Watson 65g 0.750" jackets in it, barely. I had to one time. I had a 15.5 twist 3-groove and it would not shoot long bullets. Plus, the lands diameter was 0.2385".

I did not realize the originator of this thread was shooting a 22 but the point I tried to make is that bullet nose ogive can really move the seating depth significantly, just as your steep leade can.

Speaking of Jeff' reamers, get us a reamer ground on his and Nick Young's 35 degree shoulder. I notice on Jeff's drawings for 6 PPC and 6-35 PPC that they all for a 0.075"-0.085" freebore length and 0.2433" diameter.
 
Jerry, As I remember, Jeff's older reamers were all set up to use Fowler bullets, so many of Jackie Schmidt's remarks would apply. From the SS equipment list, it seems like Jeff is making his own bullets now. I don't know any of the details of his newer bullets.

Jeff Summers is one of the best shooters I know. His equipment list is usually shows older, solid, proven stuff -- you don't often see anything "new." Certainly nothing new just because it is new, or somebody did well with it at a match or two.
 
I don´t know about the .224 bullets ,but in my 6 PPC with Gentner
65 gn BT I reach the lands sooner than with Barts Ultra. Anyway, both shoot great.
 
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