every published set of data, if collected independently and not just copy/pasted from another source, is going to be different.
no two barrels slug *exactly* the same. there will always be differences, even within a given tolerance range.
no two barrels will have the same chamber - even SAAMI specs are a tolerance range of acceptable dimensions for a given caliber
no two barrels - mind you i'm talking a typical production grade button rifled barrel here, what you'll find on 95% or better of retail shelves - even those produced consecutively, to the same base spec, on the same machine will have the same rifling twist. there will always be a difference - however slight... (a 1:10 spec may produce a 1:9.8 and then a 1:10.2 twist rate, just for an example)
no two lots of powder will have the same burn rate. they'll all be very close, but never identical.
and that doesnt even begin to discuss environmental differences that effect powder burn rate and ballistics.
with those peices of information in mind, yes it can make a difference. how much of a difference is going to depend on how those variables stack up.
being that how much of a difference is the only real question, thats why a chrono was recommended to you.
Originally Posted By: ohihunter2014
Upon talking to a couple people that reload that round I commented on how the powder seemed dirty after about 40-50 rounds it took a lot of patches to get a clean one and they asked how much powder and when I told them they said I was on the low end and needed to go higher I was underpowered. I don't own a chronograph and cant afford one right now so just judging on the book.
some powders dont burn efficently until you acheive a specific density. every powder is going to be a little different in that respect. However case fill % is not always the only answer either. Sometimes (often) neck tension can play a role, what primer you're using, temp, etc....
if you're seeing a lot of sooting on your case, that means you're not getting enough pressure to seat the case mouth into the chamber wall before the bullet is starting to move. this is almost always a sign of too low of pressure. however - that doesnt mean you're outside of the performance range of the projectile you're using either. Or outside of the performance range of your specific firearm.
the kicker is, with rounds like the .45-70 - there are often 3 different data sets out there based on the age of the firearm in use, and the relative strength of its chamber.
for older firearms like a trap door gun - you'll find data that even though its used with smokeless powder is speced for pressure tolerances for more traditional firearms that the caliber was engineered around. these loads max out at around 25000 CUP.
you'll also find "standard" loads that are used in most modern - like the 1895 marlin, loaded to around 40,000 CUP - load data thats going to be quite a bit stouter than the low pressure stuff
and then you'll also find full house data for firearms with high quality modern chambers/barrels - like a ruger #1 - that will take a more common smokeless pressure range (50,000 CUP)
bearing that in mind, if you're using the hornady 300gr HP (#4500) with 1895 marlin data, you should be fine at even relatively low power loads from the 1895 data set - those would be considered "mid range" velocitys for the trap doo data.
so while your friends may be right that its "underpowered" thats a very loaded term with a lot of shades of gray in there. that will depend on both the firearm being used and the projectile being used.
which is why i stand by my statement that someone may well be filling your head full of mush - even if they're doing so just to add another knotch to their man card, or simply through a lack of information when making the claim.
[edit] with all of this in mind, you can see why its very important when i stressed that reloading is not just opening a recipe book and picking the recipe for beef wellington that you like. Sometimes incorrect data choices can lead to VERY VERY bad consequences. You'd never want to use Ruger #1 data in a trapdoor, or marlin 1895. The result could be catastrophic - for both you and your firearm. I dont say that lightly either.
its also a perfect example of why you'll see folks over and over say "NEVER TRUST INTERNET DATA" - without at the very least verifying it against multiple sources, and then doing a proper load development to test it in your firearm as well.
