Large Rifle vs Magnum Rifle Primers

[GregLaROCHE]

Can someone advise me on how much magnum primers increase chamber pressure? I’ve not been getting complete powder burn in my .45-70 and a friend said to try magnum primers. I’m using Vectan Tubal 3000. It’s supposed to be good for this round, but if magnum primers don’t work I may try a faster powder. Any reason or danger in trying the magnum powders?

[Dieselhorses]

From my understanding, a magnum primer ensures that slower burning powder (widely used in magnum loads) will burn more efficiently. I'm sure someone here has a better explanation- I've thought about that often also. And then I've heard some folks tell me they use "either/or" in magnum loads/regular loads with no noticeable differences.

[gpidaho]

If you're not getting the powder to complete burn I'd see if the magnum primer helped. With that load I don't see a problem. Not THAT much difference in my opinion. Gp

[John McCorkle]

Two things I think go into the difference...

From what I understand there is a measurement called "bristance" (spelling may be off) which is basically how much fire comes out of the primer...more for magnum to set the slower powder burn better....

Secondary is the harder or tougher primer cup to allow a bit higher pressure before blowing a primer....once saw a really nice chart that laid out the bristance and psi ratings for sm and lrg pistol and rifle by manufacturer....I'll see if I can find a link

Sent from my Moto G Play using Tapatalk

[GregLaROCHE]

Thanks for the advice. If others have ideas please keep them coming.

[murf205]

Greg, brisance is the "force" of a primer charge. With a reasonable load in a 45/70, you should not need a magnum primer. CCI uses the same cup thickness for magnum and standard primers, but the flame temp is higher for magnums, according to CCI. If you are loading light loads with Vectan 3000 (which is on par with 4895 and TAC) you might want to up the charge weight IF....you are not close to max for the gun you are using. If you decide to try a magnum primer, back up a couple of grains first and work up.
What are you shooting it in? How well does it shoot?

[Dieselhorses]

Brisance /brɪˈzɑːns/ is the shattering capability of a high explosive, determined mainly by its detonation pressure. (http://www.castingstuff.com/primer_t..._reference.htm)

Here is a thread you may find useful...
http://castboolits.gunloads.com/show...es-for-powders

[chutesnreloads]

I would first ask if the load with unburned powder is giving the accuracy desired?If the answer is no then by all means keep working toward a better load.If the answer is yes I'd say so what?...A little unburned powder from an accurate load is acceptable.Many 45-70 loads will leave unburned powder in the barrel

[John Boy]

Read this article and reload accordingly ... https://www.chuckhawks.com/primers.htm

[samari46]

I use the CCI magnum primer with 54.5 to 55.4 grains of IMR 4350 in the 30-06. Didn't affect either the pressure or velocity all that much but did show more consistency from shot to shot. I've used this load in about 4 Winchester model 70's. 3 match rifles and one standard rifle. When I sold the standard I furnished the load data with it. Bumped into the buyer about a month after the sale. He kept raving about how accurate that rifle was. And my Sako 75 Hunter now discontinued also in 30-06 does shoot this load with a 165 Nosler ballistic tip very accurately. Been shooting this load for many years. Hope this helps. Frank

[303Guy]

I would first ask if the load with unburned powder is giving the accuracy desired?If the answer is no then by all means keep working toward a better load.If the answer is yes I'd say so what?...A little unburned powder from an accurate load is acceptable.Many 45-70 loads will leave unburned powder in the barrel

My late uncle who was an armourer in WWII in North Africa told me of sweeping up unburned powder kernels after .50 Browning machine gun shoots on the range.

Those 'unburned' powder kernels are not actually unburned - just not fully burned. Notice they are a paler color.

[lotech]

No definite rule on this. If you're shooting a less than maximum load, try both primers. Chronograph and shoot some groups for comparison.

[fredj338]

Can someone advise me on how much magnum primers increase chamber pressure? I’ve not been getting complete powder burn in my .45-70 and a friend said to try magnum primers. I’m using Vectan Tubal 3000. It’s supposed to be good for this round, but if magnum primers don’t work I may try a faster powder. Any reason or danger in trying the magnum powders?

Whether pressure goes up a significant amount when switching to a hotter primer is powder & load specific. I find slower powders gain a bit more pressures than faster powders & loads near the max show greater gain than say midrange loads.
When I am working accuracy loads for rifles & will use just one primer to develop the load. When it looks good, I will swap diff brands & even try a mag primer to see if I can squeeze a bit better accuracy out of the load. If the load is at max & I go to a mag primer I will usually back the load off 2-3/10gr depending on the powder.

[RangerDan]

I also shoot the 45-70 in both a Marlin and an original trapdoor. From my experience the mag primer does increase pressure some so when switching from standard to mag reduce load some and work up or down according to pressure signs. When working up loads for my two 45-70's I started with standard primers and worked up loads then switched to mag's and followed above procedure. It seemed to me that the mag's left less unburnt powder that standard. Also a tight crimp will help with powder burning.

[waksupi]

Whether pressure goes up a significant amount when switching to a hotter primer is powder & load specific. I find slower powders gain a bit more pressures than faster powders & loads near the max show greater gain than say midrange loads.
When I am working accuracy loads for rifles & will use just one primer to develop the load. When it looks good, I will swap diff brands & even try a mag primer to see if I can squeeze a bit better accuracy out of the load. If the load is at max & I go to a mag primer I will usually back the load off 2-3/10gr depending on the powder.

This is pretty much my process. Primers are usually the last variable I test.
As was said, it is common for the .45-70 to have unburned powder left in the bore.

[Tom W.]

I've tried both w/ mouse fart loads for fire forming 30-06 a.i. loads. Nothing different that was apparent to me. I loaded up some 30/30 loads last week or so that the book said to use magnum primers. I dunno why, but I kinda like to follow their suggestions.....

[murf205]

Can someone advise me on how much magnum primers increase chamber pressure? I’ve not been getting complete powder burn in my .45-70 and a friend said to try magnum primers. I’m using Vectan Tubal 3000. It’s supposed to be good for this round, but if magnum primers don’t work I may try a faster powder. Any reason or danger in trying the magnum powders?

Greg, if you have access to it, try Accurate 2015. I use it in my 45/70's and it is the cleanest burning I have tried and it does not need a mag primer. Tell us what rifle you are shooting. Most of the time the SLIGHTLY higher pressures will burn cleaner but if you are shooting a trap door, remember that the only thing that gets stronger woith age is wine and cheese, not rifles for sure.

[redhawk0]

I only use Magnum primers with ball powders. The powder balls form a tighter "nit" column of powder than stick powders (more spaces between the grains). It takes more "fire" to get through the ball column to burn efficiently.

redhawk

[GregLaROCHE]

Greg, if you have access to it, try Accurate 2015. I use it in my 45/70's and it is the cleanest burning I have tried and it does not need a mag primer. Tell us what rifle you are shooting. Most of the time the SLIGHTLY higher pressures will burn cleaner but if you are shooting a trap door, remember that the only thing that gets stronger woith age is wine and cheese, not rifles for sure.

I’m shooting a Marlin I bought in the 80’s. It has iron sights with a peep hole I had installed at the back. It was my primary protection against bears in the deep Alaskan bush. The sights worked great for quickly acquiring a target, but has a lot the be desired for accuracy shooting, which is where I am now. Thinking of improving the sights, but don’t necessarily want to scope it.

I noticed not all of the powder burning and a friend told me to try magnum primers. I just don’t want to go too far and over pressure it. Maybe it’s not a big deal.

I’m thinking about a faster powde might do the trick too.

[EDG]

For the 45-70 Vectan 3000 is a relatively slow powder.
The only way to get it to all burn is higher pressures and higher velocity.
If you want all the powder to burn at lower velocity you need a faster burn rate like 4227.
I use the discontinued SR4759 at about 1300 fps. It all burns in a 30" barrel. If I reduce my loads just 2 or 3 grains I get unburned kernels left in the bore.
Today the nearest extruded powders in burn rate to SR4759 are 4227, 2400 and 5744. Do not use ball powders...