Barnes suggested load discrepancies - 308WIN

[RatFink]

Has anyone compared the differences between the old and new Barnes manuals for .308win?
The current posted one lists H4895 as 44.1gr compressed as the max load, while the old version lists 45gr non-compressed as the max load for 150gr TSX/TTSX.

Can someone with way more experience than me, please shed some light on this? Obviously I know one should use the most up-to-date load data, but I wouldn't expect a change like this.

 

[Ganderite]

That difference could be a different lot of powder or testing in a different rifle.

That is why they publish a START load and the velocity of the Max.

Start low and work up and observe the speed limit.

 

[jethunter]

The TSX and TTSX are different lengths. I think Barnes has recently decided to use the same load data for both bullets to prevent someone using the wrong data, which could happen easily with the bullets having such similar names. So the data has become a bit more conservative because of the longer bullet which can create higher pressures.

 

[cold-soaked]

I had the same question so I emailed customer support at Barnes. This was the answer I received:

"Any time data is re-shot it will be different, there are many, many variables that contribute to the pressure a round produces, such as the lot of powder, brass, primer. The chamber in the individual gun, the barrel etc. in fact if you see data from one book to the next and it is the exact same you can be sure it was not reshot. Realize, that you also have a different gun, powder lot etc. So we recommend you start at the min. charge and work up watching for pressure signs, you may easily be able to get to the higher charge from the number 4 manual in your gun.
We recommend starting at .050” off the lands, then once you determine the powder and charge, adjust your COAL in and out to see what your individual gun prefers."

 

[stubblejumper]

Start low, work up,and don't worry about the max load listed in the manual. If I loaded my 7mmstw according to the new manual max load, I would have expected excessive pressure issues.

 

[Ltbull01]

Have a look at the COAL. If one is shorter, it might compress the powder charge.

 

[stubblejumper]

Have a look at the COAL. If one is shorter, it might compress the powder charge.

And when dealing with monumental bullets, the shorter COL may have a longer jump to the lands, which a tally results in less pressure.