Well you didn’t say what brand of plains rifle and how old. for that mater what your shooting for a projectile .
Is it a lyman GPR ? , CVA , Remington , Browning , mark well ?
are you shooting a round ball ? t
he above is going to dictate the safty of the issue
even though others have said yes, based on that alone I would say" NO" they are not safe in your rifle .
You are also correct in that they are also better suited for new rifles and the manufactures say so . However that doesn’t mean they are safe in all of them eather .
Read the manufacture recommendations , follow them
The problem comes in diameter. they are not recommended for some rifles becouse the pellet diameter is less /far smaller or sometimes over sized to the bore . Do you know the true bore of your rifle ?
Many traditional rifles , even still today do not have a standard bore and can actually very .010 “ + or -” from barrel to barrel
So your barrel may say 50 cal but it could actually be a 48 to 52
This brings up the warnings on many brands saying Do NOT CRUSH .
If they are to small for the bore then one has to crush them or they can actually create a situation where the ball is not properly seated and thus the powder has an air space . This relates a seriously un safe situation
If the bore is undersized then in order to load , you have to eather force them into the rifling such as with a conical . Also however if in this even , a person ends up braking or crumbling an amount of the pellet .
Whats wrong with crushing the pellet ?
Pellets are designed to exert a given amount of pressure per pellet .
However just as with on the powders if you take a given amount and crush it finer it causes the pressure to increases . Sometimes considerably
When pellets first came out they carried a use label stating what brands were safe to use the pellets in .
Today they have went to disclaims such as
i wont post the whole warning just the sections i think pertain to your question . you can read them here if you wish
HODGDON web site
http://www.hodgdon.com/data/muzzleloading/pellet-warnings.phpGENERAL WARNINGS
DANGER EXTREMELY FLAMMABLE: Pellets are extremely flammable. Failure to follow warnings and instructions for use, or misuse of this product in any way, may cause personal injury or death to the user or bystander, as well as damage to the firearm and other property. Use Pellets only in strict accordance with loading instructions
7. Do not subject Pellets to impact or friction
11. Pellets are intended to be use in place of granular powder. Do not combine Pellets with loose powder. Do not combine Pellets of different caliber sizes.
14. Do not break, cut or modify Pellet by any means.
INTENDED USE
Triple Seven and Pyrodex Pellets are designed for use only in newly manufactured muzzleloading, in-line rifles of 50 caliber, 54 caliber, and 45 caliber. Use Triple Seven only in a 209 primer ignition system. Pyrodex may be used with standard cap, musket cap or 209 primer ignition systems. Use only the correct caliber Pellet designated for the given caliber rifle. They are designed to be used with saboted bullets or conicals together with a fiber wad. Any other use of the Pellets is not recommended. Triple Seven Pellets are not for use in cartridges, or with patched round ball. Pyrodex Pellets may be used in cartridges.
MISUSE WARNING
Use of Triple Seven Pellets and Pyrodex Pellets in sidelock muzzleloading rifles, in flintlock muzzleloading rifles, using a patched round ball, or the use of conical lead bullets without a fiber wad is NOT recommended. Due to variations in the size and type of flash channels of such rifles, as well as different rifle bore diameters, and conical bullet sizes, hangfires (a delayed ignition of the Pellet) or an improper gas seal of the projectile may occur. These conditions could cause the projectile or a burning Pellet to exit the barrel in a hazardous manner, which could cause personal injury or death to the user or bystander, as well as damage to the firearm.
there is also another issue that folks often disregard with pellets . They don’t “AGAIN “ follow the manufacture recommendations as far as maximum loads especially in the modern where its common to here folks state the load 3 or 4 pellets .
MAXIMUM LOAD WARNING
45 and 50 CALIBER RIFLE:
45 Caliber Pellets come in one size: 50 grain
50 Caliber Pellets come in two (2) sizes:
1) 50 grain volume equivalent which equals 50 grains of loose powder by volume.
2) 30 grain volume equivalent which equals 30 grains of loose powder by volume.
The maximum load per shot should never exceed total Pellets containing more than 100 grains volume equivalent. That means, no more than:
45 Caliber 1) Two (2) 50 grain Pellets
2) Three (3) 44/45 caliber 30 grain Pellets
50 Caliber 1) Three (3) 30 grain Pellets, or
2) Two (2) 50 grain Pellets, or
3) One (1) 50 grain Pellet and one (1) 30 grain Pellet
54 CALIBER RIFLE:
54 Caliber Pyrodex Pellets come in one size only:
60 grain volume equivalent which equals 60 grains of loose powder by volume.
The maximum load per shot should never exceed 120 grains (2) Pell
ok so their you go . i would sugest that you go to the HODGDON site i link above and read the full warning and use statments
the ask yourself if YOU fell they are safe ?. remember none of us here most likly will be with you when you shoot them , so we have no real consiquenses if something goes wrong . so the real desion is yours and yours alone .
i tell you this i dont shoot them , will not shoot them . Myself i dont think they are safe in any weapon modern or traditional for a number of reasons .