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375RUGER
08-02-2012, 04:20 PM
A comment in another thread prompted me to ask about this.
here is the commment "Brass appears to be notched for indexing the case in the same postition with each firing. A fellow I used to know did this with his BPCR for shooting silhouettes. He would also breech seat his projectiles into the bore, then chamber his charged case. "

This reminded me of the 1st No.1 I bought, 20 some years ago. A more experienced loader (of smokeless and holy black) said, and I've never forgotten this, " No. 1. Great rifle. Just drop a bullet in the tube and shove a case full of powder up behind it."

Since I don't, yet, load BPC, How common a practice is this? Have you or who do you know that does it? Do you have to have long leade to be able to do it?

oldracer
08-02-2012, 05:15 PM
Well, I don't compete but the few folks that I have talked to in the San Diego area all index their cases. Some said they did it because others do it but Doug Knoell explained it to me this way and said he fire forms the cases and since the chamber may not be exactly and perfectly round, especially after the guns starts warming up, putting in the case exactly the same will give the same seal every time. He said he tried numbering the cases, I.E. #1, #2 on through the cases for a string of shots but that did not seem to help so he does not do it.

So I notch my cases too.

Gunlaker
08-02-2012, 06:36 PM
I'd say breech seating is not all that common these days. I've just started playing with breech seating in my new CPA rifle. It's chambered specifically for breech seating tapered bullets. If you want to find out more about it you might want to do some reading on the ASSRA web site.

Chris.

Mark85304
08-02-2012, 06:48 PM
It's not just the BPRC shooters that do this. I indexed my smokeless cartridges for pistol silhouette in the 80s for the same reason, everything the same from shot to shot. After initial fire forming, I only neck sized my cartridges so the cartridges fit the chamber the same each time I loaded it.

John Boy
08-02-2012, 06:53 PM
I'd say breech seating is not all that common these days. I've just started playing with breech seating in my new CPA rifle. It's chambered specifically for breech seating tapered bullets. For Schuetzen matches with the 32 & 38 calibers, breech seating is quite common. Paul & Gail Shuttleworth shoot all their matches this way using Hoch bullets in their 32-40's. 248 to 250's are not uncommon for them in scope matches

Indexing cases is in the minority but some BPCR shooters do it. Also some shooters index the their cast bullets when reloaded. Mold lines at 0 and 180 degrees.

Now for the next topic for discussion ... how many`shooters weigh and index their primers? Raise your ... [smilie=s: [smilie=1:

MT Chambers
08-02-2012, 08:11 PM
With my 25/20SS and 32/40 breech seating provides better accuracy then fixed ammo by a wide margin, some of the disciplines may not afford enough time to breech seat bullets. Breech seating with Black Powder may require wiping the bore between shots, it does for me.

375RUGER
08-02-2012, 09:52 PM
Now for the next topic for discussion ... how many`shooters weigh and index their primers? Raise your ... [smilie=s: [smilie=1:

OK I'll bite. weigh, I get that. But how do you index a primer? align the anvil?

Reg
08-02-2012, 09:55 PM
:killingpc:groner::groner:

25ring
08-02-2012, 10:26 PM
With a centerpunch----carefully!

sharps4590
08-03-2012, 07:16 AM
When I shot competitively I indexed the bullet in the case and the case in the chamber. Now that all I do is hunt and shoot for enjoyment I'm not quite so particular, unless I'm looking for the nth degree in accuracy from a rifle. In my rifles it did make a difference.

John Boy
08-03-2012, 10:08 AM
But how do you index a primer? align the anvil?
Yes, the primers are seated with one end of the anvil perpendicular to the index mark on the case where the mold lines are also in line with the index mark.

The Coriolis Effect is then calculated and the complete round is seated in the chamber 90 degrees reverse of the Coriolis motion of the Earth. The following equations calculate the Effect dependent where in the world one is shooting at. Presumably in the Northern Hemisphere where the rotation of the Earth is clockwise

Formulas - http://en.wikipedia.org/wiki/Coriolis_effect
* Vector formula
* Then the vector formula is multiplied by the mass of the relevant object (bullet) to produce the Coriolis force

OK Ruger, you got it now?

Gunlaker
08-03-2012, 10:55 AM
For Schuetzen matches with the 32 & 38 calibers, breech seating is quite common. Paul & Gail Shuttleworth shoot all their matches this way using Hoch bullets in their 32-40's. 248 to 250's are not uncommon for them in scope matches

Indexing cases is in the minority but some BPCR shooters do it. Also some shooters index the their cast bullets when reloaded. Mold lines at 0 and 180 degrees.

Now for the next topic for discussion ... how many`shooters weigh and index their primers? Raise your ... [smilie=s: [smilie=1:

Indeed. But I'd also argue that Schuetzen shooters aren't that common either :-). I expect that there are, at least, dozens of BPCR shooters for every Schuetzen shooter. At least this seems to be the case in my part of the world. From what I can see, the closest matches to me are about 1000 miles away unless I cross the border with my rifles.

Chris.

375RUGER
08-03-2012, 11:06 AM
Yes, the primers are seated with one end of the anvil perpendicular to the index mark on the case where the mold lines are also in line with the index mark.

The Coriolis Effect is then calculated and the complete round is seated in the chamber 90 degrees reverse of the Coriolis motion of the Earth. The following equations calculate the Effect dependent where in the world one is shooting at. Presumably in the Northern Hemisphere where the rotation of the Earth is clockwise

Formulas - http://en.wikipedia.org/wiki/Coriolis_effect
* Vector formula
* Then the vector formula is multiplied by the mass of the relevant object (bullet) to produce the Coriolis force

OK Ruger, you got it now?

Shoot. I've been doing that all along, I just thought everybody was.

Wayne Smith
08-03-2012, 11:10 AM
Yes, the primers are seated with one end of the anvil perpendicular to the index mark on the case where the mold lines are also in line with the index mark.

The Coriolis Effect is then calculated and the complete round is seated in the chamber 90 degrees reverse of the Coriolis motion of the Earth. The following equations calculate the Effect dependent where in the world one is shooting at. Presumably in the Northern Hemisphere where the rotation of the Earth is clockwise

Formulas - http://en.wikipedia.org/wiki/Coriolis_effect
* Vector formula
* Then the vector formula is multiplied by the mass of the relevant object (bullet) to produce the Coriolis force

OK Ruger, you got it now?

But only with artillery shells!

375RUGER
08-03-2012, 11:10 AM
When I shot competitively I indexed the bullet in the case and the case in the chamber. Now that all I do is hunt and shoot for enjoyment I'm not quite so particular, unless I'm looking for the nth degree in accuracy from a rifle. In my rifles it did make a difference.

Did you have your mould marked in some way so you know which side of the mould was which? If you just used the parting line, how could you tell if the boolit was aligned 180* off?

montana_charlie
08-03-2012, 12:54 PM
Did you have your mould marked in some way so you know which side of the mould was which? If you just used the parting line, how could you tell if the boolit was aligned 180* off?
Look at the base where the sprue was cut. That mark is almost never perfectly round, so it tells you which way the bullet sat within the mould.

CM

trevj
08-03-2012, 01:42 PM
Hazy memory here, but... Don't the BPCR Silhouette rules actually say that you are supposed to be shooting fixed cartridges (ie: no breech seating) for competition?

I know the Breech Seating is pretty common in the Sheutzen crowd, some even still use a barrel extension and muzzle load the bullet, but I was pretty sure that the BPCR folks were all about the fixed ammunition.

Cheers
Trev

wills
08-09-2012, 09:08 PM
Let’s see: you have about twelve minutes to shoot sighters and ten rounds for record. You would have to be pretty quick on your breech seating, even if the rules did allow it.

I have read indexing works if you can measure the case wall thickness at the head, and mark the thickest or thinnest spot, but just indexing a point on the case doesn’t help.

375RUGER
08-09-2012, 09:33 PM
That brings up an interesting point about indexing cases.
So far I have been assuming that one would make a mark then chamber the cartridge with the mark in a particular orientation then fire. No you have an as fired case that you can install in the chamber the same each time as long as no agressive sizing is done.
I'd like to hear more about the methods and theories of what wills is talking about. And is just another step in the process of the method I described?