I loaded some 454 Casull's and 460 magnums using CCI small rifle and Winchester large magnum rifle primers respectfully. The rounds would not fire in my 460V but would fire in my Thompson Center pro hunter.

I removed the grip on the 460V and checked the strain screw and it is tight. The gun has never been modified, and would fire factory Hornaday 460's and 454 Casull's with no problems.

Is it possible that my 460 is not hitting the rifle primers hard enough, and can I replace the rifle primers with pistol primers?

Both of those calibers require the use of rifle primers in the reloading data, right? If so, then I wouldn't try subbing in pistol primers with full on loads as the cups are thinner and you would probably run into primer piercing problems. And with large primers, rifle primers are a bit thicker than large pistol primers so pistol primers would be setting a bit deep in the primer pocket in the 460 S&W case. Maybe try some Federal primers instead of CCI and see if they will fire if you can find some maybe.

2 things to look at with your S&W. Check firing pin length and maybe replace the mainspring.

So are the primers showing a good dimple? What brand Primers?
Are you sure the rounds sitting fully into the cylinder?

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Dave

The only thing to add is to check that all untested cartridges have a fully seated primer. In a odd case the pin may be moving the primer forward.

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Front sight and squeeze

Do factory loads still work okay in it now that the handloads aren't?

The 460 should be able to ignite the rifle primers without issues so something obviously changed.

Large pistol primers are used in the 475 Linebaugh & 480 Ruger which are 50K psi cartridges. You don't say what power you're loading the 460 Mag to but if they're not max (60K) loads, LPPs should be fine within this constraint. I've used them in the 460M & 500M, with reduced loads & moderate powders, without issues.

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Waiting for the break of day

I am loading the 460's and 454's with H110, the 45 Colts I have loaded with tightgroup and large pistol primer work just fine.

The primers are seated flush, I am using RCBS bench mount primer tool. I ran out of factory 454's and 460's last week when I was doing comparison shots with factory to hand loads.

460's are loaded to 41.3 grains H110
454's are loaded to 28.5 grains H110
Using the same bullet 255 grain FP from Extreme bullets.

I will check and see if they have some new stuff at the range today and give it a try.

This may seem a bit unrelated, but I make sure the primer pockets are cleaned and the primers are bottomed, not just flush, with rifle primers in pistol cartridges. The slightest bit of cushion or space might just make the difference with a revolver.

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Science plus Art

You did not state which CCI primer you were using. I agree that you may have not seated the primer full depth in the pocket, with is required to provide a solid base for the anvil. check out the attached link for cup depth for the different primers. Note the difference in the CCI 400 vs the CCI 450. You may want to change to a primer with a deeper cup or even check you loading procedure to make sure you are priming full depth. For decades, I have hand primed everything to make sure of a good job. That's a fun thing to do watching TV in the evenings, hand primer in hand with a bunch of casing and looking a the latest boob tube presentation.
http://www.accurateshooter.com/techn...sure-analysis/

Seat the primers until they hit dead bottom in the pocket and then add a tiny bit more pressure, in theory this extra little bit of pressure is supposed to sensitize the priming compound for easier ignition. I'm not sure if this is right but I always hit the bottom and gave a little extra squeeze in the hand primer tool lever .
All my primer problems stopped when I stopped priming on/with the press , went to a hand held priming tool and bottomed them out.
Those instruction to seat primers .00X or "just below flush" just may not be correct with all primer pockets.
If you do try pistol primers in rifle primer pockets be aware that pistol primers are .0075 to .008 inch shorter than rifle ... make sure you bottom them out in the pocket when using them.
Gary

Easy check. If the round fires second strike, its your reloading technique. Far too many reloaders baby the primer seating process. The primer needs to bottom so the anvil has something to push against. Push harder, It is that simple.

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NRA Cert. Inst. IDPA CSO

Did you compare the impressions made by the firing pin on the primers between the new and reloads Had similar problems when some small rifle primers left in my primer went into my .40 reloads, they seem much harder then sp's and wouldn't fire. impressions were weak

A little FYI for you:

Ballistic Tools - Articles - Minimum and maximum primer and primer pocket dimensions

A firearm should fire any primer that is not defective. A firearm with a marginal primer strike has just that, a marginal primer strike.

I reseated the primers the other day and they worked fine in the revolver today.

That is why I like my RCBS Bench Priming Tool so much. It has a fantastic feel and you can feel each primer bottoming out in the primer pocket. And it is easy on the hand, wrist and arm too.

I'm glad you found the problem.

I truly hope you didn't reseat the primers in the loaded rounds. That can be very dangerous and should not be done.

You have a fun gun and a good hunting gun there. I'm glad you worker out the problem fairly quickly.

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Freedom is never free!!
SWCA #3437

I've had a problem with Winchester large rifle primers, but it's unconfirmed whether or not the primers were at fault. I made a batch of Garand ammo that was working well, before and after I tried these rounds. The rounds gauged perfectly in a Wilson gauge and there was no problem with feeding. This was so for several cartridges from that same box of primers. I can't blame the primers, but it is awfully fishy.

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"He was kinda funny lookin'"