I have seen data or use where large pistol primer was used in 45/70 with cast bullets........have anyone used large rifle primers in 44mag round that was going to be used in breakaction rifle........just playing with new rifle ....using 429244 mold sized to .430

The big difference in large rifle vs large pistol and small pistol vs small rifle is the thickness of the metal. Pistol primers will pop a little easier. Most modern pistols will pop a rifle primer just fine. Reduce your load and ease back up. You will be fine.

About the only problem arises when pistol primers are used in rifles with a floating firing pin like on AR's. Pistol primers will sometimes allow a slam fire. Multiple rounds with a single trigger pull.

I don't know the true answer but I Would Not Take that advice from Danny!!
Reloading is serious stuff!

That may be but giving out reloading data on the internet is ill advised.

Anyone should get a reloading Manuel and follow it .

I've seen horrible advice on several forums over the year.
Not saying yours is Danny but the OP should consult a manual.

there are

large rifle and large pistol which have the same same diameter but mine measure 0.120 for LP and 0.128 for LR

small pistol and small rifle are the same diameter and mine measure the same depth 0.128


the reason large pistol primers get used in reduced loads is so that they don't back out of the pocket or force the shoulder forward.


since a trapdoor 45-70 is loaded well withing the pressure limits of a modern large pistol primer it works fine.


using a large rifle primer in the 44 mag break action as long as you reduce the load for the greater fire and pressure coming from a large rifle vs a large pistol AND it fits without protruding below the base.

while not ideal should be fine in these times of primer shortage.
there are a lot of people using Magnum pistol primers and magnum rifle primers because it was all they could get.
you are doing it at your own risk but with a reduction in powder charge it should be ok.

he should consult a manual none of which will have this data. because manuals don't take into account shortages.

it is then up to the individual reloader to educate themselves as best they can and decide if it is a risk they are willing to take.

Danny is correct, so is bucksnbears. A loading manual is a must. However there are substitutions that can be made in one direction safely but not in the other. Lrg rifle primer in a pistol ctg when fired in a rifle is one of those that can be done safely providing that the powder charge is reduced by 5% as a safe starting place. Note! Some powders do not permit a reduction in charge weight. WW 296 is one that comes to mind, the manuals only list one chg weight for that powder and some manuals go as far as noteing that Winchester does not recommend reducing charge weights with 296.A lrg rifle primer in a pistol ctg that is fired in a pistol is not . The difference is in the strength of the action the ctg is fired in. Revolvers and simi autos pistols are simply not designed to handle the higher pressures. The large rifle primer has a larger priming pellet that burns hotter and longer in duration thus causing higher pressures . In a rifle action, probably ok, in a pistol action maybe not.
There are a number of variables. For example a T/C Encore is basically a single shot rifle action that will handle the much higher pressures of rifle cartridges such as the 309JDJ. 7/30Waters. 30/30 win 45/70 etc.
Sometimes the variables get very specific. For example the S&W 500 mag depends on which brand of brass you
use. The loading manuals use a large RIFLE primer in Starline brass, whereas a large PISTOL primer is used in Hornady brass.
In conclusion, the forty four Remington Mag is a pistol cartridge that is chambered in single shots, revolvers, simi auto pistols and a wide variety of rifles from single shot break action, lever action and Ruger even made a simi auto carbine for it. A large rifle primer with a powder and charge weight listed for pistol loads is probably ok in your rifle. Just be sure that those loads don’t find their way into a pistol.

GREENCOUNTYPETE Is spot on and mentioned the difference in primer pocket depths and corresponding differences in primer dimensions as well. I got lost in the weeds and didn’t mention that variable. Well done Sir.

If you go to the hodgdon reloading page and look up 357 magnum, 158 grain bullet, for an example, you will see that the starting load for w296 is 15 grains and the highest load is 16.7. If you change powders to H110 you will see that the load is the same. That is because they are the same powder. Not from a different source but the same powder in different containers.

https://www.hodgdonreloading.com/data/pistol

You can look up 44 mag or 410 shotshells and you will see the same thing.

With 15 grains of w296 and a 158 grain bullet, in that 357 mag, the listed pressure is 28,600 CUP. At 16.7 grains it is 40,700 CUP. This is with a small pistol magnum primer.
If you have only small rifle primers, start at 15 grains of w296, check for over pressure indicators, increase your charge by a half grain and check again, do not exceed 16.7 if you want a max loading, have no over pressure indication, you will be fine.

Again, do not use pistol primers in a semi automatic rifle with a free floating firing pin such as an AR has.

If your shooting a 357 magnum cartridge in a rifle like the henry lever action, pistol primers are not a problem.

here is a good reference for max safe pressure. make sure when your looking at load data to compare cup to cup and psi to psi. they are not the same thing. you will have a pretty good idea how safe the starting load is if you try a different primer. do not reduce starting loads. to little powder can be as dangerous as to much powder.

http://www.lasc.us/SAAMIMaxPressure.htm

Exactly, THAT is why many of us just call the manufacturer.

Manuals do take into account a lack of common sense, and parts that can be blow off when you blow up a gun. I bet you can't find it in any manual where it says to substitute things out due to a shortage is fine. I am trying to figure out what a shortage has to do with what you use reloading. Very poor advise at best.

hodgdon says 3.6 grains is the starting load for 9mm with 124 grain bullet and titegroup

it is risk assessment, he is a grown man and it is for him to make.

in Bosnia they learned if they used a 7.62x51 nato round with a wrap of wire around the rim it would fire from a 7.62x54r rifle those were the rifles they had but were running out of ammo the smaller 7.62 nato could be had. Yes it is dangerous , yes it split the case. but was it less dangerous than the alternative?

is 44mag ammo in 2020 USA worth the risk ? his choice. It may not be.

the reality is that a lot of people are substituting Magnum primers in loads right now because that was all they could get. people make substitutions every day from the manual. it is their risk to take with their equipment and body, there are applications like Quick loads that will let you work out the calculations for expected pressure with different non book loads.

reloading manuals define maximums with a specific case , powder , primer and projectile

for decades reloading manuals listed just a max and a bullet for the cartridge you were expected to do the math of a 10% reduction unless otherwise specified and then work up your load.

every day people load other than that specific bullet , several manuals offer data specifically on just a weight of bullet without every detail about the bullet.

there is the world of cast bullets , reduced loads , mouse fart loads some of this is in books and some of this is personal experimentation after understanding the principals.

I though I was clear there is risk and that risk needs to be understood by the user so that they can take steps to reduce that risk and that it is their responsibility to understand that and their decision.

I’m curious as to which manual is used by individuals when they create a brand new cartridge? Send a technical drawing to Dave Kiff at PT&G. A drawing of dimensions and shoulder angles a body taper side wall and neck length and diameter of a cartridge that doesn’t exist. Mr. Kiff then creates a reamer based on that drawing and the next thing you know a cartridge is brought into exsistance that has NO LOAD DATA anywhere.
There a hundreds of cartridges in existence that went through that process. Some of them you have heard of,
25-06 , 22-250, 257 Roberts, 8mm-06, 454Casul, 35Wellan. None of these were developed by the “manufacturer”
they were created by individuals in their own shops and later standardized by the major manufacturers when they adopted them. This is why the 25-06 REMINGTON, 22-250 REMINGTON are named that. They started out as wildcats designed in small shops by people that understood the principles.
P. O. Ackley once said in a phone conversation when asked for load info for a cartridge he designed,
8mm-06 A.I., START with the MAXIMUM CHARGE WEIGHT for the 8mm-06 and work up a half grain until you see signs of excess pressures then back off a half grain and you’re there!