Seating the bullet to the groove

.284 · December 28, 2009, 03:07 PM

I have a S&W 629 Classic 8 3/8" barrel 44 mag. I use RP brass, CCI 350 magnum large pistol primers, W296, and Sierra 210 gr JHC. Also, I use RCBS dies and data from the Sierra manual.

My question is this, The bullet has a crimp groove (canelure I believe is the correct terminology) and I noticed that the end of the case is just below the groove. Is this a problem? In order to crimp the case so that it is the middle of the groove I would have to seat the bullet about .010 deeper. Is that a problem? I use 26 grains of powder, am I going to change the pressure to a dangereous level by seating deeper?

I guess any info that I have asked about or hadn't thought of would be greatly appreciated.

NWPilgrim · December 28, 2009, 03:19 PM

First, any change in component or seating depth (shorter) should be accompanied by a reduction in the charge by 5%-10% and then work up if you feel the need. 26 gr of W296 must be close to maximum as that would be a stiff load in .44 mag. Reducing that by a grain would still give plenty of oomph.

Second, I have never read anything that explicitly states how much of a change in seating depth results in increased pressures. Is .002" enough to cause concern? 0.010"? Nobody seems to know for sure, so caution should be the watchword.

Third, revolver rounds, especially full house magnums, should be roll crimped in a cannelure to prevent the bullets in the chambers working their way out under recoil and jamming the cylinder. So, yes, seat and crimp to just below the top edge of the cannelure. If that creates a shorter OAL then in your load data then reduce the charge by one or two grains. Or find another data reference that uses the same OAL as your cannelure crimped loads will have.

GeauxTide · December 28, 2009, 03:31 PM

Adjust your die so that you are seating the bullet to the top of the cannelure. You should have your crimp set so that the entire groove is filled by the end of the case - FIRMLY. If your primers are showing pressure with the seating/crimping you described, back off one grain. The 44Mag with H-110/296 should have heavy bullet pulls for uniform ignition.

December 28, 2009, 03:07 PM	#1
.284 Senior Member Join Date: July 8, 2009 Location: davison, michigan Posts: 665	Seating the bullet to the groove I have a S&W 629 Classic 8 3/8" barrel 44 mag. I use RP brass, CCI 350 magnum large pistol primers, W296, and Sierra 210 gr JHC. Also, I use RCBS dies and data from the Sierra manual. My question is this, The bullet has a crimp groove (canelure I believe is the correct terminology) and I noticed that the end of the case is just below the groove. Is this a problem? In order to crimp the case so that it is the middle of the groove I would have to seat the bullet about .010 deeper. Is that a problem? I use 26 grains of powder, am I going to change the pressure to a dangereous level by seating deeper? I guess any info that I have asked about or hadn't thought of would be greatly appreciated. __________________ Guns have only two enemies, rust and politicians! Deer are amazing creatures....so please don't burn the sauteed onions and I'll pass on the steak sauce, thank you.

December 28, 2009, 03:19 PM	#2
NWPilgrim Senior Member Join Date: September 29, 2008 Location: Oregon Posts: 2,346	First, any change in component or seating depth (shorter) should be accompanied by a reduction in the charge by 5%-10% and then work up if you feel the need. 26 gr of W296 must be close to maximum as that would be a stiff load in .44 mag. Reducing that by a grain would still give plenty of oomph. Second, I have never read anything that explicitly states how much of a change in seating depth results in increased pressures. Is .002" enough to cause concern? 0.010"? Nobody seems to know for sure, so caution should be the watchword. Third, revolver rounds, especially full house magnums, should be roll crimped in a cannelure to prevent the bullets in the chambers working their way out under recoil and jamming the cylinder. So, yes, seat and crimp to just below the top edge of the cannelure. If that creates a shorter OAL then in your load data then reduce the charge by one or two grains. Or find another data reference that uses the same OAL as your cannelure crimped loads will have. __________________ "The ultimate authority ... resides in the people alone. ... The advantage of being armed, which the Americans possess over the people of almost every other nation ... forms a barrier against the enterprises of ambition." - James Madison

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

December 28, 2009, 03:31 PM	#3
GeauxTide Senior Member Join Date: April 20, 2009 Location: Helena, AL Posts: 4,423	Adjust your die so that you are seating the bullet to the top of the cannelure. You should have your crimp set so that the entire groove is filled by the end of the case - FIRMLY. If your primers are showing pressure with the seating/crimping you described, back off one grain. The 44Mag with H-110/296 should have heavy bullet pulls for uniform ignition.