Breech seating

[GWarden]

I joined the group about a year ago, and in my intro I mentioned I breech seated for some of my rifles. The question was asked if I would explain how it was done and maybe show a few photos if possible. Well, here it is almost a year later and I hope I can answer the question on breech seating. Starting at the top, a plugged case that can be used for breech seating. Hopefully you can see that the brass plug extends past the mouth of the case. When the bullet is placed in front of the plugged case and both pushed into the rifle and the action closed the bullet is pushed into the rifling and the base of the bullet will be in front of the case. Usually a rather soft bullet mix is used in breech seating; 25:1 or even softer. Rifles that are set up for breech seating will have a tapered area so that the bullet; which is also tapered will have a good fit for the bullet. The second from the top is a "push seater". The bullet fits down in the case, and when pushed into the chamber the seater will push the bullet ahead of the mouth of the case. Third and fourth seaters are "toggle seaters". As the name implies these seaters will do the best job of seating, but cannot be used on all single shot rifles. Will at a later time; much sooner than a year show some photos of the seater with a rifle, and also how breech seating improves accuracy over fixed ammo. Hope this helps on "breech seating.
bob

 

[GWarden]

This photo shows my Ruger #1 in 375H&H with the toggle seater made for the rifle and the tapered bullet in place int he seater to go into the chamber. When the handle on the seater if pushed forward it pushes the bullet ahead of the case into the rifling. I am using a tapered bulleet, but it is a factory chamber, but still works with he soft bullet being inserted.
Bob

 

[GWarden]

Hope you can see this photo clearly. The top target is ten shots 100yds with fixed ammo in the Ruger #1 375 H&H. Bottom target is the same load, but with the bullet breech seated, also 10 shots 100yds. Hope I briefly explained breech seating, and the photo of the targets show how breech seating improves accuracy. If any questions or comments, I will do my best to answer.
Bob

 

[Brad]

The seater doesn’t attach to the stock in any way? I would have figured it would need to to keep the case from just moving to the rear instead of the bullet going into the rifling.

Keep it coming, this is something I know very little about. Excellent photos and description.

 

[GWarden]

Brad
I will take another photo showing the breech seater as it fits and seats the bullet. A picture is worth a thousands words and I'm not real good at explaining things at times. Will post later tonight.
bob

 

[S Mac]

That is a quite a improvement. Thanks for sharing.

 

[fiver]

it removes the flippity floppity that can take place in the transition between case and full round straight barrel.

I hope this helps some understand my method of using light neck tension and long seating in fixed ammo, and letting the bolt closing do the final seating of the bullet in the tight neck rifles a bit better.
it isn't as good as full breach seating, and the bullets I use are a lot harder, but it is where I got the idea from.

 

[GWarden]

Brad
This photo shows the breech seater in place before the bullet is pushed into the rifling. It is clear in the Ruger #1 how the seater is held in place before the lever is pushed forward for seating the bullet.

 

[GWarden]

This photo shows after the lever has been pushed forward and now the bullet has been fully breech seated.
bob

 

[GWarden]

it removes the flippity floppity that can take place in the transition between case and full round straight barrel.

I hope this helps some understand my method of using light neck tension and long seating in fixed ammo, and letting the bolt closing do the final seating of the bullet in the tight neck rifles a bit better.
it isn't as good as full breach seating, and the bullets I use are a lot harder, but it is where I got the idea from.

Fiver
I had always used the method you mentioned for fixed ammo, as far as seating the bullet out so that when the bolt is closed the bullet was engraved by the rifling. I thought this surely would result in the best accuracy. I happened to read an article on the 6mm with cast bullets. In this article the author got the best accuracy when he seated the bullets deeper and the bullets had to jump on firing before they were engraved by the rifling. This seemed to go against everything I had heard and what seemed logical. I tried this with my 6mm with cast bullets. When I went for the bullets being seated to where they engraved the rifling, to being seated a bit over .030 from the rifling my groups really tightened up. I have not had a chance to try this in any of my other bolt rifles. May start a new post on this soon and show the results.
bob

 

[Brad]

Ok, so there is a little tit on the side that engages the slot for the breech block and that retards reward motion of the case.
Now I see how it works. I assume that pretty much all breech seaters are rifle specific as they need a similar method to stay in place when pushing the bullet forward.

 

[GWarden]

Brad
You are correct, seaters are specific for the rifle. I used the push seater for years, and then closed the action with the plugged case for getting uniform seating depth for each round fired. That worked great for many years before I went to the toggle breech seater. If you go back to the photo that shows the four different breech seater, the number three is for a CPA rifle in 32.40
I wish I could find the article about a fella that built a bolt rifle in 32/40 and throated it for tapered bullets and breech seated. It would be real interesting to see that set up.
bob

 

[fiver]

a jump to the rifling is one way to manipulate things.
in the XCB tests I lost accuracy when I went to a jump, I think the slippery bullets I was using was part of why I got things to work.
they all just bumped the rifling and nestled into the throat area and the case was slid up over them.
the .001 total clearance around the case neck probably had a whole bunch to do with why.

 

[GWarden]

a jump to the rifling is one way to manipulate things.
in the XCB tests I lost accuracy when I went to a jump, I think the slippery bullets I was using was part of why I got things to work.
they all just bumped the rifling and nestled into the throat area and the case was slid up over them.
the .001 total clearance around the case neck probably had a whole bunch to do with why.

Fiver
I wonder if this is just another example of how each firearm is an entity unto itself, what works great in one is the opposite in another. In breech seating we see this in the distance the base of the bullet is seated ahead of the mouth of the case. One fella did a lot of work on just this, and found that there is that sweet distance that will put the first shot from a clean barrel in the same spot as the following shots. Seems like for most rifles the first shot from a cold/clean barrel will be outside the group. I find it interesting to work with all the variables that go into cast bullet shooting. The one part that gets overlook is the person behind the rifle concerning accuracy. That is a whole different topic . You all have a blessed Christmas.

If anyone would like a copy of the article; believe it was by Jim Carmichael, on the 6mm and accuracy and seating depth send me your email and I will send a pdf file.
bob
Iowa

 

[Spindrift]

@GWarden ;thank you for an excellent explanation, I have little knowledge of breech seating, but it is an interesting method! One question, though; how do you retain the powder in the case? Point the gun upwards when loading the case? Wax plug?
Merry christmas to you, too!

 

[Bret4207]

Excellent post! Having read quite a lot on the Schuetzen Era and the likes of Pope, Schoyen (sp), etc. this is something I always wished to experiment with but just never had the time, $$, rifles, etc. I do find it interesting that various seating depths work out differently in different rifles. But we see that even with different bullets in the same rifle. Hey, if it was easy as follow steps 1, 2 and 3 and they'll all go in the same hole then it wouldn't be any fun at all!

 

[GWarden]

@GWarden ;thank you for an excellent explanation, I have little knowledge of breech seating, but it is an interesting method! One question, though; how do you retain the powder in the case? Point the gun upwards when loading the case? Wax plug?
Merry christmas to you, too!

Spindrift
Some do use a wax plug, or a thin fiber wad. I have never done either. One is using a rather small amount of powder in breech seating and with plain base bullets the velocity is 1400 fps or less in most instances to prevent leading. In the 32/40 I may be using only 14.4 gr of Alliant 300MP, and in the 38.55 it is a small amount, as well as the 375H&H. I will drop the powder into the case from a measure, tap the base of the case on the bench to settle the powder in the case for uniformity from shot to shot. I then very gently insert the case into the chamber and close the action. Remember this breech seating is done with a single shot action such as the Ruger #1, Ballard, CPA. With Black Powder and breech seating one uses a over powder wad since the case is full. Also a over powder wad is crucial in BP and breech seating. A factor that really makes a noticeable difference with BP is compression of the powder. I have targets that show this as I was working on accurate loads. As little as .010 compression is noticeable in group size.
bob
Iowa

 

[4060MAY]

being the klutz I am
I use floral foam, about .200 thick , pressed into the mouth of the case
I have a Ruger chambered in 32-40 with a breech seat throat
once you dump 12 grains of ball powder into a Ruger No.1 or 3 action, you will find a way not to do it again
this is how we learn

 

[fiver]

Bob got the PDF this morning.
thank you.

we worked on that first shot thing and come to a couple of conclusions.
the big one is lube related and there is a fairly consistent friction variable, once that first shot is fired the whole thing is repaired and your not dealing with it any more.
except that you are over long strings with some lubes, then it's the opposite effect.

 

[GWarden]

The photos I posted earlier were with the Ruger#1 and breech seating, this rifle was not set up for being used for breech seating. The two targets shown here are from a CPA in 32/40 that has a tapered throat that was made to match the tapered bullet. These are 5shot groups/ 100yds.
bob