This weekend I shot my CPA 32-40 in competition for the first time.  The barrel is a Bresien (sp?) with a 1:15 twist and the bullet is a Saeco 732 weighing 205 grains.  I am charging with 14.2 grains of IMR 4227 for an estimated 1490 fps.

At 100 yards the group was good, but in reviewing the target I noticed a bit of yawing. At 200 yards the bullets were definitely yawing at about a 30+ degree angle and groups were poor.

Need a little hand holding to get this problem straightened out.

Thanks,

A bit of "yawing"  keyholing is fine IF they go where they should go in a nice group.
Increase the charge in small increments (2 tenths) until keyholing stops, or pressure problems start showing up.

I'm surprised that you saw a bit of yawing at 100.  I shoot that bullet with black powder (~1350 fps ) and I have never seen yawing at 100, but I do very often at 200 depending on the weather.  Cold weather is worse.

If you knock out a seated bullet, is it engraved uniformly all around?  If it's not central to the bore it will bump up such that it is out of balance.

Chris.

Length of the bullet and not the weight which varies quite abit based on alloy choice should be whats being referenced. The 15gr. load I believe is indicative to Rick MacHales accomplishments at Raton and his typical load was actually 15.1grs of 296 pushing a 234gr. bullet in a gain twist barrel ending at about 11. Not quite apples and oranges per-say. A freind is using a comparable bullet to yours, 205gr. Darr FN in his 15 twist Bresien without issue and he also shoots it in his 16 twist Darr rifle. Elevation here I believe is quite abit different and also a factor but I would take a close look at your muzzle crown you should not be having a problem with bullet stabilization. I would be looking more towards your verticle dispalacement as an indicator of the need to up your powder charge if the tipping is just a slight amount and it could be a false indicator by the target backer being used and especially so if using cloroplast by chance and or not standing plumb to the world but leaning, twisted and or both.

JLouis

Schuetzendave wrote on Mar 7^th, 2017 at 9:19am:


If not following these guidelines will accuracy and/or stability suffer?  I have a 1/15 twist .32-40; 208gr non-tapered bullet (fixed) is stable at 1400-1450fps.  Can I assume accuracy will improve with a lighter bullet?

Schuetzendave wrote on Mar 7^th, 2017 at 5:28pm:


What happens that cause the seater to change?

Schuetzendave wrote on Mar 7^th, 2017 at 8:27pm:


I assume you are talking about smaller cases like RKS, ect.

Guess I need to get out more    I never noticed any differences that I could not attribute to other factors in my 33-47.  Mostly shooting on the coast and Spokane being so steep, my offhand stock is definitely a limiting factor. 

I wonder what high humidity in the Midwest would change?

DW it really has nothing to do with all of the Voodo but practice, practice, practice and more pratice. Most who are not serious cannot tell when their rifle is shooting up to par or not and they just keep sending lead down range with only a hope and a prayer. But as long as they are having a boat load of fun while doing so it really does not matter to them in the least as should be and it more than meets their own exspectations and I admire them for doing just that and simply just having fun. 

JLouis