Post deleted by fanner50

i'm not good on internals, but look to make sure the round is going into the chamber far enough to allow the gun to lock up properly.
remove the barrel n take a feeler gauge for comparison and see how much of the case head protrudes "above, even or below flush" with the chamber end of the barrel.

take the feeler gauge n see how much barrel to frame gap there is with the barrrel on the action. close the action on consecutively thicker blades till it just does slide out without binding. this should tell you your "barrel to frame gap".

if the factory round sits below flush with chamber ...... or if the factory round sits above flush more than the measured barrel to frame gap, it will not allow the action to lock up.

also.........does the GNR barrel by reeder have a short throat that will not allow that bullet/loaded round to go deep enough into chamber to lock up? meaning the bullet is engaging the lands too hard to close on.

hope this helps....or at least begins the process of figuring it out.

30-30ackley improved rounds will fire standard factory 30-30 ammo. not sure about the GNR improved cases surely gary reeder could help ya out on that.

if none of this helps.............i've heard of hammer springs in the action getting weak and needing replaced.

Sounds like a hammer spring or headspace problem to my. Try another barrel on that frame and see if it goes boom. If it does then I'd say headspace...you may need to seat the bullets out into the lands to keep the case from bumping ahead when the fp strikes the primer...this would cause the light strike syndrome.

I'm thinking hammer spring. These are factory 30/30 rounds going into a 30 GNR chamber to fire form. The key here is the first one went boom and the rest haven't. The rim of the case sits on the extracter and in the barrel OK, so I think I'll look at hammer springs first. Anyone know where I can get an extra power hammer spring?

One thing it could also be is the falling block safety has some dirt or grease that is not allowing it to fall out of the way quick enough. This is usually more troublesome in cold weather. I pour boiling water over mine to clean out all the oil and grime, and then relubricate. Only had it happen to me once, but that fixed it.

As explained above, given that you are fireforming, headspace is the most likely culprit.

I had the same thing happen with my 375jdj and I asked these guys what they thought and I got the same recommendations on the headspace and the hammer spring, I bought a headspace gauge and extra power hammer spring from bellm and after installing the spring and adjusting my headspace about .004 I havn't had a single misfire.

I discovered after a closer inspection of the safety mechanisum that there was a brown sludg so I removed the role pin to discover a mess of brown rusty goop and a spot on the actuator that appeared to be contacting the frame. Cleaned everything real good polished with dremel and lubed. Now she goes bang once again. 1st rule of gunsmithing make sure all is clean lubed and working properly. Thanks to all for the replys. Fanner50