why such a large difference in data between sources

[Usmcinfantry1988]

ok guys so in referencing some older load data for Barnes XLC in 280 rem I found that the max powder charge is 55gr of IMR4350 and me being me I always try to cross reference to some other manual just to confirm I'm in the right range for working up a load. so I looked at noslers manual for 160gr bullets and its showing the max powder charge for 160gr with imr4350 is 50.5gr. I understand some differences for length of bullet/ bearing surface etc.. but the same weight bullet with a difference of 4.5gr in powder for the max charge . Am I crazy or is this normal to have that much difference between max charges of different manuals? looked on gordonsreloadingtool as well and its showing the 55 gr being way OP, let me know what u think. thanks guys !

 

[Roninco]

The powder may have been slightly reformulated since the older data was published. Also, various sources may use different case/primer combinations which affect maximum loads.

 

[dgp3006]

I have been using the Barnes XLC blue coated bullets since they came out. The load data for them is in the older Barnes manuals and it is correct. The coating is very slick and doesn't build pressure like the current TSX or TTSX.

 

[Usmcinfantry1988]

Ok that makes sense. Dang I feel stupid now I miscalculated that powder charge was raised due to slick coating ! Thanks for clearing that up man !

 

[Wolf76]

Won't speak to this particular cartridge, but there are a number of key variables. Brass(capacity can vary a bunch), primer (amount of flame/heat can vary even within the same designation), bullet shape/construction material (mono vs cnc), bearing surface, COAL, and even the test barrel used(some pressure sooner). Lets not forget the lawyer influence as well.
And ultimately the book MAX doesn't matter because your configuration will let you know what the max is. Look at it as a suggestion and make an educated guess as to where to start. Everybody here will tell you to start low work your way up safely.
I do completely understand your frustration as its shared by many.

 

[RogerPA]

ok guys so in referencing some older load data for Barnes XLC in 280 rem I found that the max powder charge is 55gr of IMR4350 and me being me I always try to cross reference to some other manual just to confirm I'm in the right range for working up a load. so I looked at noslers manual for 160gr bullets and its showing the max powder charge for 160gr with imr4350 is 50.5gr. I understand some differences for length of bullet/ bearing surface etc.. but the same weight bullet with a difference of 4.5gr in powder for the max charge . Am I crazy or is this normal to have that much difference between max charges of different manuals? looked on gordonsreloadingtool as well and its showing the 55 gr being way OP, let me know what u think. thanks guys !

The Barnes XLC was a coated bullet that reduced barrel friction to the extent Barnes load data for this bullet was always different (higher max volumes) than that for their original X-bullet. Barnes discontinued this bullet with the introduction of their Triple Shock line. The coating generated fouling, amongst some other problems. I would disregard load data for this bullet when comparing it to others.

 

[dgp3006]

As a side note to my previous reply, the last Barnes manual that had the XLC data in it had a lot of errors that was acknowledged by Barnes and corrected. You just had to print the correct data off a computer and tape appropriately in the manual.

 

[Usmcinfantry1988]

Side note understood , thank you for that !

 

[FrogFire7]

Won't speak to this particular cartridge, but there are a number of key variables. Brass(capacity can vary a bunch), primer (amount of flame/heat can vary even within the same designation), bullet shape/construction material (mono vs cnc), bearing surface, COAL, and even the test barrel used(some pressure sooner). Lets not forget the lawyer influence as well.
And ultimately the book MAX doesn't matter because your configuration will let you what the max is. Look at it as a suggestion and make an educated guess as to where to start. Everybody here will tell you to start low work your way up safely.
I do completely understand your frustration as its shared by many.

I was just going to comment the same... The guys that print the reloading manuals (at least thinking of the main Hornady one I use) tell what brass and primers they use, and I believe even the gun and barrel length. When I started reloading, I took the "book max" as gospel. Knowing what I know now, it's pretty obvious that their max charge may be higher, or significantly lower than mine based on brass, seating depth (that is a big one, in my experience), etc. I use the book to get a good idea where to start my pressure test ladder and go from there.

 

[dgp3006]

Another comment regarding performance for me about those XLC bullets. I have used them in a 7RM, 300WM, and a .338/.280 AI. I found them to be very easy to tune to at least better than MOA and usually multiple loads around half MOA. The barrels on those rifles are Hart, Kreiger and Shilen. Have not had any problems in cleaning down to steel any time I wanted to but generally clean what would be considered often. I just hunt with them each year, sight in and clean after the season.

 

[asd9055]

I noticed that a few years ago, that newer manuals had lower maximums. I reached out to Hodgdon. Their reply was that powders have not changed, but primers have As well as the ability to measure pressures. Those are the two reasons. Always start low and work up!

 

[Usmcinfantry1988]

good info , thanks guys !!

 

[RidgeTop]

Older manuals did not have the measurement capability and accuracy of newer test methods. Also, it is possible powder had changed over a decade or two.
I saw a load for a .38spl that was twice the max load of a few other manuals max. Could have damaged the firearm. Always work up.

 

[duckdog388]

I have been using the Barnes XLC blue coated bullets since they came out. The load data for them is in the older Barnes manuals and it is correct. The coating is very slick and doesn't build pressure like the current TSX or TTSX.

I have used Barnes XLC in .284 since the 90's and love them. Do you know a source that has them. Bill