Magnum Primers & Leading...

[BCB]

I observed something this morning that is a bit baffling! I was at my range just shooting a few 358429’s from my Ruger Security-Six. My previous reloads were put together with CCI-500’s. Well, yesterday a put some together with CCI-550’s as my CCI-500 supply is getting low and I use them exclusively for my 38 Special.

I load 15.0 grains of H-110 for a M.V. of 1247 fps and 6.0 grains of Scot 453 for a M.V. of 995 fps. (The CCI-550 loads were not chronographed so I don’t know the velocity change from 500’s to 550’s) Some leading is always noted at the forcing cone for a distance of about 1”. Today, shooting the rounds loaded with the CCI-550’s, there was virtually no leading in the same location as previously described! Any thoughts on that? Velocities probably aren’t the answer—except that maybe it has something to do with how quickly the velocity is achieved? Maybe someone else has experienced this…BCB

[Bass Ackward]

I observed something this morning that is a bit baffling! I was at my range just shooting a few 358429’s from my Ruger Security-Six. My previous reloads were put together with CCI-500’s. Well, yesterday a put some together with CCI-550’s as my CCI-500 supply is getting low and I use them exclusively for my 38 Special.

I load 15.0 grains of H-110 for a M.V. of 1247 fps and 6.0 grains of Scot 453 for a M.V. of 995 fps. (The CCI-550 loads were not chronographed so I don’t know the velocity change from 500’s to 550’s) Some leading is always noted at the forcing cone for a distance of about 1”. Today, shooting the rounds loaded with the CCI-550’s, there was virtually no leading in the same location as previously described! Any thoughts on that? Velocities probably aren’t the answer—except that maybe it has something to do with how quickly the velocity is achieved? Maybe someone else has experienced this…BCB


BCB,

Good to read you again.

My guess is that you are shooting undersize bullets for your throat and counting on obturation for the seal. Probably using ACWW or harder too. If so, then it sounds like the magnum primers are raising the pressure faster so that a seal is accomplished before you blow off your lube. The obturated bullet seals the throat and then the forcing cone area before it is sized down to bore. So no leading ocurs from gas cutting or no lube.

At least that's the way it works for me.

Do I win?

[Ricochet]

That's exactly what I was thinking. Faster pressure rise, better seal.

[BCB]

Thanks Guys,
That is sort of what I was thinking. Getting the velocity up to speed a bit quicker which would mean greater pressure at the beginning, I think. Regardless, I am amazed at the change in leading and it was with both the slow burning powder as well as the fast burning powder. I will need to shoot more than just a box of reloads to see if this holds true, but if it does, that throws another parameter into the "no leading" equation! Too complicted sometimes...BCB

[GP100man]

i wasted alot of alloy hardening boolits before learning the obtrutation (curve)


GP

[45r]

used small rifle primers in my 357 shooting 158 rcbs swc and lyman 148 wc and real cheap hard lube mixed with moly -graoh grease and no leading and one inch groups at 35 yards.4.6 trail boss for the 148 wc and 7.0 power pistol for 158 swc.cheap lube cost 70 cents a stick.too hard without the moly grease but worked great with the wc load.one ragged hole after another.going to use rifle primers from now on.

[44man]

The only concern I have is that some SR primers can have a harder cup and some revolvers do not have the mainsring power to reliably fire them. Since most SR and SP primers are the same size or within .002" of being so, if the spring is strong enough, they work but might increase pressure with a max load so a workup is needed.
I would NOT do this with a LR primer in place of a LP because the cups are .010" longer on the LR primer and can fire on the recoil plate. They also have very hard cups and are hard to fire in revolvers. They generate a lot of pressure too.
Most .357 loads benefit from the mag primer but the proper boolit fit can make the standard primer very accurate too, something I have not found in the .44 and .45 where the standard primer has always given the best accuracy even with jacketed bullets. Very, very cold conditions need the mag primer so it is a case of testing where you live and when you shoot although in very cold Ohio winters, the standard primer was still perfect. When the weather gets warmer, standard primers in the .44 and .45 are better. The .357 can go either way and it might be because of the physical size of the primers. Just not that much fire in them.
The biggest problem still comes down to the size most molds are from the factories. As long as we have no choice on the boolit size with the molds we buy, it will always be a problem. Yes, a powder or primer change can effect leading and accuracy with undersize boolits unless the boolits are very hard. No matter what primer, we would be better served with throat size boolits. Why factories only make bore size molds has always baffled me. Must be a throwback to the muzzle loader. They make size dies but most boolits do not need them, if you notice, they come in bore sizes. Larger boolits that need sized for the throats would be a lot better.
As I have said over and over, do not get stuck on any one type primer because the books tell you so. You must test for yourself with each different gun and condition to see what works for you. If your .357 works better with a mag primer, it doesn't mean the .44 needs it because it says magnum! I say the same for powders. If H110 shoots good, hey, try 296 too, it just might tighten the groups. Some guns prefer it even though it is the same powder made by the same company but they are different in the specified burn rate for Hodgden and Winchester.
I continue to say to never get stuck on the same thing because some book said so.

[Ricochet]

I doubt that the factories make near bore (groove) size moulds out of ignorance. I think they do it because that's more standardized than throat dimensions. In many cases, boolits sized to be a tight fit in the throat will make a bulged case neck that won't chamber readily. And sizing dies are usually made to accommodate a groove-sized jacketed bullet. It can be tough to seat an oversized boolit without damaging the case.

[44man]

Ricochet, I have never found a throat size boolit that would not chamber in a revolver when seated. Long over throat size boolits will not go in the throats and will prevent chambering but those that do not extend into the throats have always chambered. Have a problem? Size the boolit! When the boolit is too small, what choice do you have?
Same in the rifle where the boolit should fit the throat. Too large? Size it! Too small and there is a problem again.
Yes, my revolver cases do expand around the boolits so I can see the grease grooves through the brass but they fall right in. Super tight chambers only need a size die to make the boolit fit.
Why do they make molds that drop .357 and .429 boolits and sell .358, .359, 360, .430, .431 and .432 size dies when they won't size the too small boolit?
I am sure you can see what I mean and you are adding something that rarely, if ever happens.
For instance, my .475 Linebaugh has a .476 bore. The throats are .4765. I chamber boolits that are .478. If they would not chamber, I would size to .477 or .4765. If the boolit cast at .475, what good would it be?
I chamber .431 and .432 boolits in my .44 that has a .430 bore. What good is a .429 boolit?
The boolits for my Browning 45-70 BPCR are .464, the bore is .459---They chamber by dropping in until I engage the rifling.
The solution to a large boolit is a size die. The solution to an undersize boolit is ZIP.
I NEVER size anything unless it will not chamber, I haven't found a problem yet and I make my molds oversize for each gun.
How many posts are here that ask about Beagling, bumping up boolits by mashing or shooting them hot or making them too soft so they expand? Does this not sound like a problem?
Do you still think the factories are doing the right thing? C'mon, you have been here long enough!

[OLPDon]

I would venture to say that the average reloader (not Caster) hasn't a clue on dia. of throat bore ect. So Manufacture's keep things a standard for the masses. Be it the right size or not as long as it sell's. Heck I have a SUV that I love and it burn gas faster then a M16 set on full auto, (just a thought)
Don

[Ricochet]

Yeah, I see what you mean, 44Man. But it also presumes that you will have to size your boolits. I love it when I don't have to! And I do agree with Richard Lee that whenever you have to size a bullet, you're correcting a defect. Got to size gas check boolits to seat the checks. But with plain base bullets, sizing them is an extra step that ought to be unneeded. If you deliberately make the moulds run large, you're going to have to size down those overfat boolits and add a step that shouldn't be part of the process.

[44man]

I don't like to size either and almost never do. I make my molds to as close to the size I want. I don't even use a lubricator for most, just rub the lube in with my fingers or pan lube, then push them through an oversize Lee or a home made tube to remove excess lube. My sizer, lubricator has oversize dies also. But if a thousandths or so needs squeezed, it does no harm and I would prefer this to a boolit that is too small where almost nothing can be done except to Beagle or lap it out, either one worse then sizing. Beagling has a tape problem and lapping will always make a mold out of round.
I don't get to some boolits right away and they age, that makes them even larger but I have not had to size any of them, in fact, they shoot better for me.
I would like to see them make .44 molds .431 or 2, .45 molds .452 or 3, .475 molds .476 or 7, .30 molds .309 or 10 and so on. These would fit over 99% of guns without sizing. If a little larger boolit is still needed, one could make them harder and age them. If too large, just a skim in a sizer would not hurt a thing. Just pan lube and run through a Lee die.
Back around 1957 I bought an NEI .44 mold that had such small grease grooves that I would make them smaller when I sized the boolits. Years later when I learned more, I found they chambered and shot better by just leaving them alone. I remember that long ago, all casters thought every boolit had to be sized. (To bore size too!) Factory lubes were so hard that a sizer was needed for everything. Leading was a big pain!

[9.3X62AL]

Lotta good info above. I share Bass' opinion on the mag primer phenomenon.

I detailed my use of a 45 Colt sizer die (RCBS carbo) with my 45 ACP cases meant for the Glock 21. This was prompted by measurements of 45 ACP factory loads that showed case diameters of loaded rounds to be a pretty uniform .469"-.470". The much-used carbo 45 ACP die sized the cases to .467", which seemed like over-working of the case wall brass to me.

[beagle]

Good post. I'll bet that even 75% of the casters have no idea what diameter they're actaully sizing to. Most casters and especially new casters buy a sizing die from Lyman/RCBS or Lee and take the diameter stamped on it for gospel. From my expereiences and I have about 90 different sizers,only maye ten of them come close to what is actually stamped on the die.

It's a good winter project to actually measure what you're getting out of that sizing die and measure several bullets with a good mike. I store my dies in film cannisters that Wally World will give up for free and record the sized measurements to 4 places on the lid.

This allows you to pretty well know what diameter you're getting from your sizing dies./beagle


I would venture to say that the average reloader (not Caster) hasn't a clue on dia. of throat bore ect. So Manufacture's keep things a standard for the masses. Be it the right size or not as long as it sell's. Heck I have a SUV that I love and it burn gas faster then a M16 set on full auto, (just a thought)
Don

[9.3X62AL]

Beagle--

I just recently began tracking actual sized results from my dies with given alloys. Have you noticed any "spring-back" size differential between (e.g.) wheelweight metal and Linotype in a the same die? I use Taracorp (92/6/2) for most of my smokeless shooting, and things seem to run about .0005" to .001" larger than given diameter of Lyman and RCBS sizers. I can imagine that larger calibers might yield wider variances, but I'm just guessing here.

[beagle]

Deputy Al....I haven't noticed any springback on my stuff. But again, I haven't checked diamteres after sizing and then again later. GCs do springback if not anealed as I've seen the outline of the check on .30/30 necks after they'd been loaded and stored for a few months so I know that's happening but the alloy I'm using seems to pretty well stay put. I use soft stuff. Normally WWs cut with some pure lead for pistols, straight WWs for rifles and some of Felix's babbit/ww mixture for the centerfire .22 rifles.

I guess the only way I'd have detected it would be during seating. I sized one batch of 3K 356402s for the 9mm 3 years ago at .3565. I did verify several before loading them this fall to verify size and they still read .3565" so I know that they didn't grow any after sizing and these were from WW alloy.

I've read of others getting springback on sizing but I haven't persued it. Guess a test is in order here this winter./beagle

[beagle]

Deputy Al.... Guess what I'm saying here is that I accept what diameter I'm getting from the sizing die as measured.

I could see that maybe different alloys would give different diameters from a known diamter die due to strethching/springback.

May be something to that but I rarely mess around with different alloys enough for it to bother my loading.

This is a good discussion. Why don't you start a new post and see what input we get?/beagle

[Bass Ackward]

Deputy Al.... Guess what I'm saying here is that I accept what diameter I'm getting from the sizing die as measured.

I could see that maybe different alloys would give different diameters from a known diamter die due to strethching/springback.

May be something to that but I rarely mess around with different alloys enough for it to bother my loading.

This is a good discussion. Why don't you start a new post and see what input we get?/beagle


Guys,


Springback is real for me. And the amount IS proportional to bullet diameter.

In some cases you can accept what size you are getting. In some cases not. If I use my 14 BHN mix after it has age hardened in Lyman sizers, I generally get what is stamped on the die because I am close enough to 15BHN. If I try to size right after molding while still soft, I get smaller bullets.

I make a lot of nose through sizers. Take 44 caliber for instance. A hole that measures .429 will throw a .4295/6 bullet out of my 14 BHN mix right after molding. Right after molding, my bullets are 9BHN. If I size after everything hardens, I get .4300/.4302 from that same die.

If I mold and water drop for two hours which is a reasonable period of time to heat up the blocks and generate a few bullets, then turn off the pot and clean up and let the bullets dry, that generally takes another half hour. Then when I start sizing the bullets are obviously out of order, I might grab a softie and at the end grab one that is already about 20 BHN. When I set the extremes aside, I get a difference of .0015 in diameter after only that long. So I won't use bullets that are water dropped unless I size 24 hours later and can get a consistent diameter. Then If I wanted a hard bullet where it matters, I have to HT in the oven again.

That's why I mold and store everything air cooled, unsized and unlubed so I have options and can get what I need later.

[44man]

Bass, now that is some great information! I never noticed that because I never get to size right away if a boolit does need sized (Very Rare.) and don't size the rest of them.
I have only noticed boolits getting harder and growing as they age. This varies with diameter, small ones grow less of course.
Growing boolits is the greatest way to fit a throat too if you are lacking a thousandths or so and just might be the reason a lot of guys say harder boolits shoot better for them, me included even though I make my molds a little larger then what can be bought.
You blow away the theory that a boolit must be sized within a half hour after casting, ( Info from Bill Ferguson. ) you wind up with all kinds of sizes and hardness plus too small of diameters.
I hope this will stay in the back of my head in case I ever need it, gettin old ya know!
Since I cast slow, never do things right away, let my boolits age, don't size, could all of this be the reason I get such tight revolver groups?
Another reason to not hurry things up!

[Bass Ackward]

Bass, now that is some great information! I never noticed that because I never get to size right away if a boolit does need sized (Very Rare.) and don't size the rest of them.

I have only written that about 10 times. It is very real. And I even wrote about my bullets growing. That one comment is good for a couple of "Your Crazy" PMs. :grin:

That is why some guys get better results from hard lead with multiple guns. If your diameter isn't perfect for that gun or the barrel has .... dimensional abnormalities or twist rate issues, you still get enough springback as that bullet is moving up the barrel to maintain seal if the bore isn't dimensionally perfect. (That is assuming you aren't one of those lube maintains the seal guys) The opposite end of the spectrum comes from soft lead guys that maintain enough pressure the whole way that their soft bullets keep obdurating to maintain the seal. When you get a guy that is inflexible on diameter or isn't paying attention to what he is producing, you usually hear him say, I can shoot soft or I can shoot hard, but I lead with ACWW.

Ever heard that one? :grin:

From rifle guys you usually hear, "You need hard bullets for anything over 2000 fps. Same, same. Tells me that they aren't as broken in as they should be. Otherwise, they could do better with ACWW. Funny thing is that I use Very hard stuff for 1600 fps loads and use ACWW for HV stuff. Opps, that sounds bass ackward again.