PLAIN BASE FIXED UNDER 1" AVERAGE

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Last Post 28 January 2013

CBA Member

joeb33050 posted this 30 November 2012

Wednesday at the range a shooter asked me if shooting plain based bullets in fixed ammunition <1"was a reasonable goal. Aside from a step-necked case in my 30-30 bench gun, I don't think I've ever been able to do it. I'd like to hear from anyone who can average under 1” for five 5 shot 100 yard groups, fixed plain base. Thanks; joe b.

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Standard Member

biddulph posted this 30 November 2012

Hi Joe, please excuse my ignorance, but what's a 'fixed base' bullet?

I'm having troubles getting that kind of accuracy out of gas checked bullets!

Cheers

James

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CBA Member

RicinYakima posted this 30 November 2012

James, Here in the US we have two types of cast bullet shooting. One is breech seating, where the bullet is forced into the rifled part of the barrel, and a powdered case is put behind it. The other is where the bullet is inserted into the case and looks and acts like “modern” ammo.

HTH, Ric

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Standard Member

Wayne S posted this 30 November 2012

joeb33050 wrote: Wednesday at the range a shooter asked me if shooting plain based bullets in fixed ammunition <1"was a reasonable goal. Aside from a step-necked case in my 30-30 bench gun, I don't think I've ever been able to do it. I'd like to hear from anyone who can average under 1” for five 5 shot 100 yard groups, fixed plain base. Thanks; joe b.What do you mean by “ FIXED PLAIN BASE” ??

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CBA Member

pat i. posted this 01 December 2012

biddulph wrote: Hi Joe, please excuse my ignorance, but what's a 'fixed base' bullet?

I'm having troubles getting that kind of accuracy out of gas checked bullets!

Cheers

James

Your not alone by any means no matter what you read on some of the forums.

"What do you mean by ” FIXED PLAIN BASE” ??"

All loaded up and ready to shoot........not breach seated. I asked a similar question a while ago in my thread about PB bullets in fixed cartridges and didn't get many replies either. One group means nothing to me and shooting at 50 yards means nothing to me. If someone is getting 1 inch or under aggregates at 100 yds with a PB bullet loaded in a fixed cartridge I'd sure like to hear about it also.

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Match Director

linoww posted this 01 December 2012

Shoot a few wallet groups under 1” yes,average NO.Like Pat says 50 yard screamer groups dont seem to correlate to screamer 100 yard groups with planbase.

George

"if it was easy we'd let women do it" don't tell my wife I said that!

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Standard Member

biddulph posted this 01 December 2012

OK, this raises the next question:

Whats the objective of breech seating? If its jamming the bullet into the lands, isn't that a bit too much of a good thing? I've been of the understanding that 20 thou off the lands was the acid test.

But, Im interested. Primarily because i have a couple of Weatherby's who's long long free bore makes the 20 thou 'rule' impossible to 'enforce'...

Any advice would be great. I've never ever thought of breech seating!

cheers and thanks to all you great guys out there, this forum is full of esoteric info!

james

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CBA Member

.22-10-45 posted this 01 December 2012

Hello, biddulph. Breech-seating has long been the recognized method of starting a lead bullet straight and true into rifling without the variables introduced by the ctg. case. Before B.S., Pope was using muzzle/breechloading..his thinking was the bullet would leave muzzle in same condition it went in..and any fins displaced by rifling would be pushed forward on bullet..leaving base true & burr-free. Modern bench-rest practices can overcome most if not all of these problems..close chambers/throats, turned case necks. Special tapered throats (Ardito)..seating out with only gas check or so in neck. All seeking to do same thing..start the bullet straight. I have always seated my .22 C.F. cast to engrave first band when action closes..As well as most of by bigger bore stuff.

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Match Director

linoww posted this 01 December 2012

I believe Pope got this system from George Schalk? Memory may be failing me though. An interesting note is that Bev Pinney is using a Muscrave bolt gun with a breech seater in a short 30-30 to .32 case and he tells me it shoots as well as his Miller did.He shot some good groups with it in Spokane when i was there last year.

"if it was easy we'd let women do it" don't tell my wife I said that!

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CBA Member

.22-10-45 posted this 01 December 2012

Yes I believe your right about Schalk..If I remember right..pope's rifling had no sharp corners. Just remembered about work Dr. Mann did with B.S. jacketed..his bullets had a base band..forward was bore-ride. Chamber/throat was machined for this bullet.

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CBA Member

argie1891 posted this 01 December 2012

i wish i could average 1 inch groups not saying i never shoot 1 inch groups but i shoot more over an inch than under. it is much easier to forget all groups except the wallet groups. i think it would be interesting to keep track of say 25 or 50 groups and actually see what was average. argie1891

if you think you have it figured out then you just dont understand

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CBA Member

pat i. posted this 01 December 2012

biddulph wrote: But, Im interested. Primarily because i have a couple of Weatherby's who's long long free bore makes the 20 thou 'rule' impossible to 'enforce'...

james

I've always thought the Weatherby throats would be perfect for cast bullets and still do although I've never had one. Get an LBT mould that casts or is sized a half thousandths under free bore diameter and you're doing what most of the the cast bullet BR shooters are doing. To pick what to order seat a bullet backwards in a case to get the free bore length, add the length of the ogive for the caliber you're shooting which is listed on Veral's website, and add to that about 1/2 or 3/4 of the neck length so the bullet will be in the neck when seated and you should be good to go. Bullet weight doesn't matter as long as everything else fits.

As an example a 300 Weatherby mag has a .360 long free bore. A LBT 30 caliber SP has an ogive length of .340. The 30 Weatherby mag case has a .330 neck length. If you used .275 of that you'd end up ordering a LBT SP bullet .975 (let's just go 1 inch) long which should weigh about 180 grains or so out of WW if you order it with one lube groove. Size the bullet a half thousandths under free bore diameter and seat it a little long so it seats on bolt closing and it might shoot pretty well.

I don't know if the .020 rule applies to cast bullets. I've always had my best luck jamming, or at least kissing if I'm using a real light neck tension, the bullet into the lands.

None of this is by any stretch of the imagination related to the subject at hand but I felt like writing something.

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CBA President

John Alexander posted this 01 December 2012

Pat,

You obviously need a 300 Weatherby to work with. I think what you describe would be a great thing to try. Mike Mohler won the nationals with a 243 which has at least as much “extra” case as a 300 Weatherby. Plain based bullets out of that big case would be interesting. Subsonic loads even more interesting.

John

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Match Director

linoww posted this 01 December 2012

John Alexander wrote: Pat,

John

Maybe with a case that big the powder gasses would be cool by the time it reached the bullets base<g>

"if it was easy we'd let women do it" don't tell my wife I said that!

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CBA Member

pat i. posted this 01 December 2012

28 grains of Varget. Sill seal wad on top of the powder. LBT gas checked bullet set up like I described with the single groove full of LBT Blue....Result.... Guaranteed seat at the winners table at the 2013 National Championship with George Damron as your personal servant for the evening. :D

On another subject. I just found a bottle of Rooster Jacket I must have bought some time in the distant past and never opened. Does anyone have any experience with it? I'm going try shooting my PB tomorrow using Blue Dot and Unique subsonic loads and while the bullets I'm using are lubed with LBT Blue something like the Rooster might be a better option to try down the road for the slow pokes. I also opened the flash hole on one case with a 9/64 drill. Read somewhere it helps with light loads. Anyone have any first hand experience?

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Match Director

linoww posted this 01 December 2012

I tried opening flash holes just once and with unique i couldn't see a difference.it was only one set of groups though.It will be interesting to see ho wit does for you.

"if it was easy we'd let women do it" don't tell my wife I said that!

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CBA Member

RicinYakima posted this 01 December 2012

For smokless, the only thing I have tried it on, it helps with loads of too slow of powder or ball powders,at least the ignition and SD's are better. When I was working with surplus ball powders, it made my 30/06 groups go from 3 1/2 inches to 3 inches. With 16.0 grains of A2400, there was no difference I could see, all groups were about 1 5/8” in the Springfield. WFIW, Ric

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CBA President

John Alexander posted this 01 December 2012

Pat,

You might try a few of the bullets lubed with LBT rolled around in Rooster Jacket. I have sometimes found that a coat of LLA helped a bullet although they had LBT in groove. It doesn't cost much to try.

John

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CBA Member

.22-10-45 posted this 02 December 2012

Hello, joe. Please forgive me for sounding dense..but what exactly is ment by “average” 5 shot group? Does this require 1” or under each and every time rifle is taken to range? Or say in a summers worth of shooting..adding up total dia. of groups & dividing by # of targets? I have never done this before..might proove interesting!