How much does this effect accuracy?

AL45 · September 6, 2015, 08:40 PM

I loaded up some .45 Colt using 200 grain RNFP cast lead bullets, HS-6, starline brass and CCI primers and did a light roll crimp right at the top of the cannelure. It turned out to be a very accurate load. I repeated the same load for today's shooting and it was very inconsistent. I looked closely at the unfired cartridges and noticed that I didn't get the bullets seated as deep as the first load and a little more of the cannelure was visible. The bullets shot low and a few shot very low. I'm certainly no marksman, but I don't string bullets vertically as bad as these were. Could improper seating depth cause such inconsistencies?

condor bravo · September 6, 2015, 09:12 PM

I think the reason for the inaccuracy is because you are using the wrong terminology.

With lead bullets the crimping groove is called just that, not a cannelure.

csmsss · September 6, 2015, 10:41 PM

Well...if it was a seating depth issue, I wouldn't expect to see vertical stringing, unless there was so little of the bullet inside the case that it was nearly falling out - and you would likely see intense fouling on the face of the cylinder and the forcing cone. My opinion is your problem lies elsewhere. Were these super-light loads?

AL45 · September 6, 2015, 11:15 PM

CMSSS, Hodgdon starting load is 11.7 grains of HS-6 with a Hornady xtp at 9500 cups of pressure. So I would say this is a very light load in my Ruger Blackhawk.

Jimro · September 7, 2015, 08:34 AM

Yes it can affect accuracy. With straight wall cartridges and low case fill the deeper seating and bullet firmly crimped in place is the best bet for good accuracy.

Even light loads in a revolver can get the "kinetic bullet puller" effect and then every shot has a different effective case volume because the bullets are at different seating depths with a different amount of case hold.

Jimro

mikejonestkd · September 7, 2015, 08:54 AM

AL45, I am not certain which load you are having issues with - in the Original post you mention 200 grain cast, but in your last post you mention the XTP bullet.

Either way, its probably a crimp issue. Generally- In my experience, cast bullets shoot best with a decent crimp.

AL45 · September 7, 2015, 09:05 PM

mikejonestkd, sorry for the confusion. The Hodgdon load data was a Hornady xtp. What I actually used was a 200 grain cast lead.

September 6, 2015, 08:40 PM	#1
AL45 Senior Member Join Date: December 12, 2012 Posts: 761	How much does this effect accuracy? I loaded up some .45 Colt using 200 grain RNFP cast lead bullets, HS-6, starline brass and CCI primers and did a light roll crimp right at the top of the cannelure. It turned out to be a very accurate load. I repeated the same load for today's shooting and it was very inconsistent. I looked closely at the unfired cartridges and noticed that I didn't get the bullets seated as deep as the first load and a little more of the cannelure was visible. The bullets shot low and a few shot very low. I'm certainly no marksman, but I don't string bullets vertically as bad as these were. Could improper seating depth cause such inconsistencies?

September 6, 2015, 09:12 PM	#2
condor bravo Senior Member Join Date: August 23, 2014 Location: Nevada/Ariz/CA Posts: 1,753	I think the reason for the inaccuracy is because you are using the wrong terminology. With lead bullets the crimping groove is called just that, not a cannelure. __________________ Ouch, the dreaded "M-1 thumb", you just know it will happen eventually, so why not do it now and get it over with??

September 7, 2015, 08:34 AM	#5
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	Yes it can affect accuracy. With straight wall cartridges and low case fill the deeper seating and bullet firmly crimped in place is the best bet for good accuracy. Even light loads in a revolver can get the "kinetic bullet puller" effect and then every shot has a different effective case volume because the bullets are at different seating depths with a different amount of case hold. Jimro __________________ Machine guns are awesome until you have to carry one.

September 7, 2015, 08:54 AM	#6
mikejonestkd Senior Member Join Date: January 3, 2006 Location: Brockport, NY Posts: 3,717	AL45, I am not certain which load you are having issues with - in the Original post you mention 200 grain cast, but in your last post you mention the XTP bullet. Either way, its probably a crimp issue. Generally- In my experience, cast bullets shoot best with a decent crimp. __________________ You are the bows from which your children as living arrows are sent forth.

September 6, 2015, 10:41 PM	#3
csmsss Senior Member Join Date: October 24, 2008 Location: Orange, TX Posts: 3,078	Well...if it was a seating depth issue, I wouldn't expect to see vertical stringing, unless there was so little of the bullet inside the case that it was nearly falling out - and you would likely see intense fouling on the face of the cylinder and the forcing cone. My opinion is your problem lies elsewhere. Were these super-light loads?

September 6, 2015, 11:15 PM	#4
AL45 Senior Member Join Date: December 12, 2012 Posts: 761	CMSSS, Hodgdon starting load is 11.7 grains of HS-6 with a Hornady xtp at 9500 cups of pressure. So I would say this is a very light load in my Ruger Blackhawk.

September 7, 2015, 09:05 PM	#7
AL45 Senior Member Join Date: December 12, 2012 Posts: 761	mikejonestkd, sorry for the confusion. The Hodgdon load data was a Hornady xtp. What I actually used was a 200 grain cast lead.