500 S&W magnum load oddities

pnewlon · April 23, 2017, 04:46 PM

I loaded up 50 rounds of 500 magnum today to try out my new toy at the range. The recoil was not nearly as stout as I was expecting, given all the hype. My 15YO daughter even shot it a few times :-)

Loads:
(25) 46gr of 300MP under 350gr Berrys, Winchester Large Rifle Magnum primer (3 grains under Alliant max load)
(25) 25gr Power Pistol under same bullet and using same primer (two grains under Alliant max load)

Easily 20% of the rounds didn't fire on first single action attempt but would always fire when hit a second time. I attempted a full cylinder in double action, not one fired. Back around a second time in single action, all 5 fired.

All the Power Pistol rounds, after firing, had fairly clean cases and no flattened primers. No apparent powder burns on the outside of the cases.

3-4 of the 300MP rounds had VERY flattened primers, the rest looked fine. The ones that flattened were also a challenge to extract. They had powder burns back on the case which caused the sticking so I don't think it was overly excessive pressure. As soon as I tapped the extractor the case 'broke loose' and extracted just fine. I found the 300MP powder in my 44 magnums to be very dirty also, but this looked like the powder was still burning as it came back into the cylinder. Every one of the 300MP cases have some discoloration/burn marks on the outside.

1. I carefully measured the powder, checking the throw weight every 3 rounds. I also visually inspect the charges of all cases before I seat bullets. Of course I likely wouldn't see a tenth of a grain difference, but I surely would have seen something that caused a louder bark and flattened primers on the 3-4 rounds.

2. I always check the primer seating depth.

3. I've been reloading since the mid-80s and I'll bet I haven't had five total failures to fire. Today I had at least ten.

Any thoughts on the failures to fire? Maybe Winchester cups are just that hard? The Alliant data used Federal 215 LRM, are they softer? Has anyone had an issue with FTF and Winchester primers? It's especially odd that NO double action shots lit off at all. Not that I'm going to be meeting a bear any time soon but it sure would stink to have 5 clicks and no bangs in that situation!

243winxb · April 23, 2017, 06:03 PM

Try different primers. If that doesnt fix it, try a new hammer spring.

THEWELSHM · April 23, 2017, 06:29 PM

What he said....

Thewelshm

flyguy958 · April 24, 2017, 08:46 PM

Seat the primers. If they fired the second time most likely they were not seated.

pnewlon · April 25, 2017, 06:55 AM

I've always set primers 'just below' flush by touch using my press. When I mic them, they show to be in the .003-.005 range below the base of the case. I bought a RCBS Universal Primer Tool yesterday and seated 25 using it. I mic'd the depth of 10, they run .010-.012 below the base of the case. I've never seen primers sit this deeply in a case. Starline brass with the 'R' designation. Can't get to the outdoor range until the weekend, anxious to see if that solves the problem. I'm betting it will..... How odd.

flyguy958 · April 25, 2017, 10:44 AM

^^^^^
Hope it does, I'm betting it will. Let us know.

243winxb · April 25, 2017, 08:27 PM

Quote:

they run .010-.012 below the base of the case. I've never seen primers sit this deeply in a case.

Seems to be a bit much.

pnewlon · April 25, 2017, 09:19 PM

> Seems to be a bit much.

That's what I thought too. I'm sure I have more to learn, but this one's got me scratching my head. I'll get a chance to give em a go this weekend.

condor bravo · April 25, 2017, 10:01 PM

Per post #4, failure to fire initially but does fire on the second strike is typically due to the primer not seated to proper depth. Yes the Win primer cups are harder than the Federal cups. I have the .460 S & W, cousin to the .500, and also use Power Pistol powder and Win primers and have never had a misfire. I have the primer recorded as Win SLR, the "S" referring to standard large rifle as opposed to magnum. The Lyman manual indicates the standard CCI #200 as the primer of choice for the .500, but the Win magnum primer for the .460. But you could try Federal primers and see if that helps. I'm not sure how I latched onto Power Pistol powder since it is not shown in the Lyman.

knapwon · April 28, 2017, 08:06 PM

Quote:

they run .010-.012 below the base of the case. I've never seen primers sit this deeply in a case. Starline brass with the 'R' designation. How odd.

Its just one of many oddities with 500 sw, I use CBC & Hornady brass, same problem. LR primers in a LR pocket, they seat too deep. Two strikes to fire means they sat too deep for pin to reliably fire first time around. Brand doesn't seem to make a difference, used Federal, Remington, CCI, Winchester. Nor does LR vs LR-Mag.

I bet if you measured the depth of the LR primer pocket you'll find they're out of spec or something.

As for recoil, I've always found my revolver's bark far worse than its bite. It probably means the compensator really works!

condor bravo · April 28, 2017, 08:59 PM

Again comparing against the .460 that really doesn't settle anything, the primers are set .002 below flush on factory Hornadies. My own loads with Win large standard rifle primers are .003 to .005 below flush with new Starline brass. I guess the OP has ruled out large pistol primers slipping into the mix. With the difference in thickness between the two, that could account for the excessive depth.

243winxb · April 28, 2017, 09:00 PM

Looks like .009" below is about maximum for a fully seated LR primer, by SAAMI standards.http://s338.photobucket.com/user/joe...wroxx.png.html

Primers should be seated flush to .008" below face of cartride case head,, when seated to the bottom of the pocket , per SAAMI.

pnewlon · May 1, 2017, 08:23 AM

> I guess the OP has ruled out large pistol primers slipping into the mix.

Yes sir, I checked that. I had opened a new box of primers.

> Primers should be seated flush to .008" below face of cartride case head,, when seated to the bottom of the pocket , per SAAMI.

Interesting. If one took the max primer dim and the min pocket dim, you'd get .011 protrusion. Seating to .008 below face would be a .019 crush.....

I got 50 rounds loaded this weekend, but didn't get a chance to go to the range (honey do list got in the way). Hope to get this resolved next Sunday.

condor bravo · May 1, 2017, 11:16 AM

pnewlon:
Can you measure the primer pocket depth of the new Starlines, or once fired and deprimed? Back to the .460s, I'm out of new Starlines for a measurement but a once fired and deprimed Starline measured .132. And I concur with your perception that the recoil of these two monsters is not nearly as bad as might be anticipated. It may have something to do with the way the grips seem to slip back in the hand after firing rather than having to roll with the punch like it was glued to the hand.

243winxb · May 1, 2017, 11:32 AM

Quote:

Interesting. If one took the max primer dim and the min pocket dim, you'd get .011 protrusion.

My RCBS ram prime unit doesnt care. It will smash them into flush.

In fact, i been smashing small pistol primers into some brass for years with it. But just bought a depth uniformer to correct 150 38 specials. The pockets were to shallow.

April 23, 2017, 04:46 PM	#1
pnewlon Junior Member Join Date: January 10, 2013 Posts: 7	500 S&W magnum load oddities I loaded up 50 rounds of 500 magnum today to try out my new toy at the range. The recoil was not nearly as stout as I was expecting, given all the hype. My 15YO daughter even shot it a few times :-) Loads: (25) 46gr of 300MP under 350gr Berrys, Winchester Large Rifle Magnum primer (3 grains under Alliant max load) (25) 25gr Power Pistol under same bullet and using same primer (two grains under Alliant max load) Easily 20% of the rounds didn't fire on first single action attempt but would always fire when hit a second time. I attempted a full cylinder in double action, not one fired. Back around a second time in single action, all 5 fired. All the Power Pistol rounds, after firing, had fairly clean cases and no flattened primers. No apparent powder burns on the outside of the cases. 3-4 of the 300MP rounds had VERY flattened primers, the rest looked fine. The ones that flattened were also a challenge to extract. They had powder burns back on the case which caused the sticking so I don't think it was overly excessive pressure. As soon as I tapped the extractor the case 'broke loose' and extracted just fine. I found the 300MP powder in my 44 magnums to be very dirty also, but this looked like the powder was still burning as it came back into the cylinder. Every one of the 300MP cases have some discoloration/burn marks on the outside. 1. I carefully measured the powder, checking the throw weight every 3 rounds. I also visually inspect the charges of all cases before I seat bullets. Of course I likely wouldn't see a tenth of a grain difference, but I surely would have seen something that caused a louder bark and flattened primers on the 3-4 rounds. 2. I always check the primer seating depth. 3. I've been reloading since the mid-80s and I'll bet I haven't had five total failures to fire. Today I had at least ten. Any thoughts on the failures to fire? Maybe Winchester cups are just that hard? The Alliant data used Federal 215 LRM, are they softer? Has anyone had an issue with FTF and Winchester primers? It's especially odd that NO double action shots lit off at all. Not that I'm going to be meeting a bear any time soon but it sure would stink to have 5 clicks and no bangs in that situation!

April 25, 2017, 10:44 AM	#6
flyguy958 Senior Member Join Date: June 27, 2009 Location: SC Posts: 200	^^^^^ Hope it does, I'm betting it will. Let us know. __________________ You can have your own opinion but you can't make up your own facts !

April 25, 2017, 10:01 PM	#9
condor bravo Senior Member Join Date: August 23, 2014 Location: Nevada/Ariz/CA Posts: 1,753	Per post #4, failure to fire initially but does fire on the second strike is typically due to the primer not seated to proper depth. Yes the Win primer cups are harder than the Federal cups. I have the .460 S & W, cousin to the .500, and also use Power Pistol powder and Win primers and have never had a misfire. I have the primer recorded as Win SLR, the "S" referring to standard large rifle as opposed to magnum. The Lyman manual indicates the standard CCI #200 as the primer of choice for the .500, but the Win magnum primer for the .460. But you could try Federal primers and see if that helps. I'm not sure how I latched onto Power Pistol powder since it is not shown in the Lyman. __________________ Ouch, the dreaded "M-1 thumb", you just know it will happen eventually, so why not do it now and get it over with?? Last edited by condor bravo; April 25, 2017 at 10:15 PM.

April 28, 2017, 08:59 PM	#11
condor bravo Senior Member Join Date: August 23, 2014 Location: Nevada/Ariz/CA Posts: 1,753	Again comparing against the .460 that really doesn't settle anything, the primers are set .002 below flush on factory Hornadies. My own loads with Win large standard rifle primers are .003 to .005 below flush with new Starline brass. I guess the OP has ruled out large pistol primers slipping into the mix. With the difference in thickness between the two, that could account for the excessive depth. __________________ Ouch, the dreaded "M-1 thumb", you just know it will happen eventually, so why not do it now and get it over with??

April 28, 2017, 09:00 PM	#12
243winxb Senior Member Join Date: July 26, 2011 Location: USA Posts: 1,730	Looks like .009" below is about maximum for a fully seated LR primer, by SAAMI standards.http://s338.photobucket.com/user/joe...wroxx.png.html Primers should be seated flush to .008" below face of cartride case head,, when seated to the bottom of the pocket , per SAAMI. Last edited by 243winxb; May 21, 2017 at 08:14 PM.

April 23, 2017, 06:03 PM	#2
243winxb Senior Member Join Date: July 26, 2011 Location: USA Posts: 1,730	Try different primers. If that doesnt fix it, try a new hammer spring.

April 23, 2017, 06:29 PM	#3
THEWELSHM Senior Member Join Date: February 20, 2015 Location: Brandon Fl Posts: 236	What he said.... Thewelshm

April 24, 2017, 08:46 PM	#4
flyguy958 Senior Member Join Date: June 27, 2009 Location: SC Posts: 200	Seat the primers. If they fired the second time most likely they were not seated. __________________ You can have your own opinion but you can't make up your own facts !

April 25, 2017, 06:55 AM	#5
pnewlon Junior Member Join Date: January 10, 2013 Posts: 7	I've always set primers 'just below' flush by touch using my press. When I mic them, they show to be in the .003-.005 range below the base of the case. I bought a RCBS Universal Primer Tool yesterday and seated 25 using it. I mic'd the depth of 10, they run .010-.012 below the base of the case. I've never seen primers sit this deeply in a case. Starline brass with the 'R' designation. Can't get to the outdoor range until the weekend, anxious to see if that solves the problem. I'm betting it will..... How odd.

April 25, 2017, 09:19 PM	#8
pnewlon Junior Member Join Date: January 10, 2013 Posts: 7	> Seems to be a bit much. That's what I thought too. I'm sure I have more to learn, but this one's got me scratching my head. I'll get a chance to give em a go this weekend.

May 1, 2017, 08:23 AM	#13
pnewlon Junior Member Join Date: January 10, 2013 Posts: 7	> I guess the OP has ruled out large pistol primers slipping into the mix. Yes sir, I checked that. I had opened a new box of primers. > Primers should be seated flush to .008" below face of cartride case head,, when seated to the bottom of the pocket , per SAAMI. Interesting. If one took the max primer dim and the min pocket dim, you'd get .011 protrusion. Seating to .008 below face would be a .019 crush..... I got 50 rounds loaded this weekend, but didn't get a chance to go to the range (honey do list got in the way). Hope to get this resolved next Sunday.

May 1, 2017, 11:16 AM	#14
condor bravo Senior Member Join Date: August 23, 2014 Location: Nevada/Ariz/CA Posts: 1,753	pnewlon: Can you measure the primer pocket depth of the new Starlines, or once fired and deprimed? Back to the .460s, I'm out of new Starlines for a measurement but a once fired and deprimed Starline measured .132. And I concur with your perception that the recoil of these two monsters is not nearly as bad as might be anticipated. It may have something to do with the way the grips seem to slip back in the hand after firing rather than having to roll with the punch like it was glued to the hand. __________________ Ouch, the dreaded "M-1 thumb", you just know it will happen eventually, so why not do it now and get it over with??