I am working up reloads for my Ruger SRH 454 Casull. I am using Starline brass, CCI BR4 primers, H110 powder, and 400 grain Cast Performance LFN bullets. Here is the problem, I am getting a lot of missfires. The fire on the second attempt. Factory ammo as not yet missfired. Any ideas what is wrong? I am posting this on gunsmith, and hand gun forum as well.

Did you replace the factory mainspring with a lighter aftermarket spring to drop the trigger pull? I put a lighter aftermarket spring in my SRH 480 to lighten the pull, and would occasionally get a failure to fire, so I put the heavier factory spring back in and it fires every time.

It's also possible you aren't seating your primers fully in the case.

Are you getting any oil or sizeing lube on your primers? I use dillon carbide 45 Long Colt dies and have not had a misfire yet. I also use winchester small rifle magnum primers. Any oil on the primers is said to deactivate them.

I did not change the spring but it may have been done before I got it. I will check the spring. As for lube on the primers that isn't the problem as I am using the carbide dies. It may be a seating problem though I will have to check that carefully next time.

Thanks Swede, and Paul.

Every time I have had a question about firearms in the last several years I have found the best answers here at Accurate Reloading.

My guess is you are not seating the primers deep enough .
On the first strike the primer is seated to full dept , on the second the primer will go off .
Only takes a few thou.
Or the primer pockets are a few thou to deep ,resulting in the same thing .
Check the primer pocket depth .
If the same as factory cases then try seating the primer a little deeper.

Johnch

I think one or the other or both of PaulH's possibilities is correct diagnosis.

I changed my SRH to weakest hammer spring from Wolffe kit and it worked fine all summer. The difference in drag as fall hunting season approached and I would begin to have misfires that would ALWAYS fire on second hammer strike. Back to factory spring and 100% firing. The Wolffe kit has three springs so I had other choices, I was just trying to prove a point and I do NOT change things in the middle of "huntin" season.

I would switch to the magnum rifle primer.
I would also get a Lee factory crimp die for it.
I got much more consistent ignition with the Lee die.

Mainspring power is indeed a problem. Too weak a hammer fall will give deplorable accuracy even if the primers go off. NEVER weaken the mainsprings on ANY gun. If you have problems with primers going off, put a new spring in.
When I was involved in the silhouette game I changed the mainspring in my Rugers once a year.
Do not try to get better trigger pulls by putting in weaker main springs or loosening the strain screw on a S&W.
All US primers are easy to set off, only military primers are tough, especially the ones for the SKS as the firing pin has no spring and will make the gun go full auto with US primers. If you drop a reloaded 7.62 X 39 shell in the chamber, with say a Winchester primer, and just let the bolt slam shut, the round will fire from firing pin inertia.
If the primer is fully seated and you still get missfires, fix the problem. It is not only dangerous but your groups will suffer.

This is pretty obvious, but the 454 does take a small rifle primer. The folks that make small rifle primers don't know that they might be used in a revolver and they are set to ignite reliably from a striking force of a rifle spring and pin.

The transfer bar on the revolver takes up energy too, so go with the strongest spring you can get and seat those primers all the way.

On the other hand misfires in the 454 are a good check on you proclivity for the dreaded flinch!!