Thread: Concentricity issues after deburring

I assume you do the two stage seating thing already??? If not...start seating projectiles,stop,rotate case half way around and complete seating stroke.....I don't measure stuff myself but those that do have done this and have said it does make measurable difference.

It is freshly annealed with only one pass on Lee FLS die (no expander) and then neck tension set with hornady FLS die with expander in and set a long way out.

Ive pulled the pin on a redding slant con gauge. Think i'll flick the hornady one to free up some space (its good on finished rounds).

Yep to the double sided FLS method and also twisting 3 times when seating. The loaded ammo is usually about 1-2.5thou off zero but i do get the odd 4 or 5 thou mutant.

Didn't Erik Cortina say concenticity isn't that important? Pretty sure I read his article saying he deliberately loaded as straight as possible and some that were way off. Tested them at a 1000yrds and couldn't find a statistical difference. He doesn't measure run out anymore. If it was a problem, then at the level he shoots at it would be rectified for sure.

Sent from my SM-A145F using Tapatalk

Of course it might be the gauge that had a burr in it lol.

Relieved i didnt stuff the guage shoving brass in it that didnt fit so well. Stupid of me. Its made of alu from deep dark china no doubt so i should treat it more gently.

I'd cleaned this twice and still had the issue grrr. But it had to be crap in there eh. Maybe just something from manufacturing perhaps

My Lyman case gauges are all made of steel so there isn't much chance of brass cases damaging them.

Originally Posted by 7mmwsm

And if you want to add a whole pile more stress to your system, buy a bore scope.

Best thing to do to your concentricity guage is smash it with a hammer.
Bore scope is actually usefull!

Sent from my SM-A556E using Tapatalk

Originally Posted by r87mm

Didn't Erik Cortina say concenticity isn't that important? Pretty sure I read his article saying he deliberately loaded as straight as possible and some that were way off. Tested them at a 1000yrds and couldn't find a statistical difference. He doesn't measure run out anymore. If it was a problem, then at the level he shoots at it would be rectified for sure.

Sent from my SM-A145F using Tapatalk

Not Eric. But on YouTube saw some joker deliberately bend them and still shot ok. As the bullet enters the throat it would get straightened I would think.

Originally Posted by andyanimal31

Best thing to do to your concentricity guage is smash it with a hammer.
Bore scope is actually usefull!

Sent from my SM-A556E using Tapatalk

Yes bore guides are really useful. But when you don't have one, the what you don't know doesn't affect you applies.

Originally Posted by 7mmwsm

Yes bore guides are really useful. But when you don't have one, the what you don't know doesn't affect you applies.

$170 its the best money I have spent in s long time

Sent from my SM-A556E using Tapatalk

Im keen to squeeze the absolute most out of my ammo. Took my new 250mm gong and planted it at 300m. Cold clean barrel shot.... totally missed.

Mind you the wind was right to left doing a solid 8mps. Not too difficult i'd have thought. 4 clicks low and 3-4 right.

2550fts with a 150gn SST 308. Rather humbling tbf.

Originally Posted by T.FOYE

Im keen to squeeze the absolute most out of my ammo. Took my new 250mm gong and planted it at 300m. Cold clean barrel shot.... totally missed.

Mind you the wind was right to left doing a solid 8mps. Not too difficult i'd have thought. 4 clicks low and 3-4 right.

2550fts with a 150gn SST 308. Rather humbling tbf.

Buy a bigger gong!

Sent from my SM-A556E using Tapatalk