Need Advice and opinions

[Bob Smith]

I'm new to the BPCR silhouette game. I have two rifles both in 45-70 and am shooting a 530 grain Saeco bullet with 62gr. 1.5 Swiss with a .060 polywad. I've benched both rifles at 100yds and about every third round I'll throw one 6" high. I've had other shooter try with the same results. It it always a verticle string on calm days. I anneal every case everytime. I'm confident it's pressure changes. I use a compression die always and I weigh every cast bullet and keep them within two grains. All my brass is Starline, I use Federal Magnum Rifle primers. I size every bullet and use SPG lube. I'm getting frustrated 6" at 100 is a BIG miss at 500. Advise, suggestions or thoughts please.

The two rifles are:
1. Persolli Sharps
2. Browning 98
One scoped and one Vermeer.

Thanks, Bob

[ndnchf]

Vertical stringing can bee caused by an inconsistent trigger pull, also your breathing and coonsisnt grip on the rifle. I would use standard primers, there is no need for magnum primers. I don't see any need to anneal the cases after every firings. Maybe once every 10 loadings.

[Don McDowell]

More powder likely will cut down on the verticle.
Fouling control can also make or break groups.

[country gent]

You mentioned the bullet wieght and model but not the alloy cast from. A good bullet cast from a lead tin alloy may help also. 20-1 to 15-1 lead tin mix may help some. Another you didnt mention is the a wad between powder and bullet. A snug fitting wad will protect powder from lube and base of bullet during ignition. Wads can be made from milk cartoons ( waxed card board), Tablet backing, Coffee can lids, cork, felt, or one I use is Napa rubber fiber gasket material .060 thick. Pour powder into case consistantly ( slowly and from about 3" above funnel) this helps to settle it some. Insert wad and seat with a plug by hand this sets wad square and flat on powder charge. Compress charge to depth needed to seat the bullet. Keep in mind heavy neck tension can bend distort these big soft bullets noses. Shoot for .0005-.001 tension or hand seat onto wad then lightly size around bullet. Neck expanders can be set up with as much as .003 tension as original. Wads, compression fouling control all can and due affect accuracy. Position, holding tension, bag technique, follow thru also affect this. Use an upright positioon hold rifle firmly but not in death grip pulling straight back into shoulder with little to no downward force on rifle. These rifles can "bend' or flex with tension causing vertical. Let the rifle recoil and follow thru. Also position rifle the same way on the rest bags or sticks the same way every time. If possible find the dead spots in the barrels nodes and place there.