Difference in Reload Data

[Bushmaster223]

I am planning on reloading using 35 gr. Bergers and IMR 8208XBR. Hodgdon's site lists min. load at 27.0 grns. and max load at 28.2 grns. I emailed Berger and they listed min. at 23.5 and max. at 26.3 grns. What's up with such a big difference? This is for a Remington R-15 with a 22" barrel.

Thanks

[Ol` Joe]

They used different lots of bullet and powder in their labs and likely different primers and brass brands or lots also.
Then there is the difference in test beds. Throats, bore geometry, chamber volume...Just as my max load may difffer widely from yours so do thiers. The data is not meant to be cut in stone but, rather a general "guide" and report of what theirs accepted.
it`s a wonder the different manuals come as close as they do sometimes.

[Darkker]

Denton Bramwell did a series of testing.... DESPITE what companies tell you, primers have ZERO effect on loadings(in 30-06 and smaller cases).

The issues come from 3 main sources.
1) Powder lot variation. If one lot is faster or slower than another.
2) jacket material lot variation. Sometimes the ingredient list makes them slightly more "sticky".
3) What is the "test" mule? is it a universal reciever, or some production gun?? Chambers are different...

Also remember that Hodgy doesn't MAKE one drop of smokless propellant. I know that Winchester is "supposed" to be responsible for loading development and pass it on. They don't, and apparently Hodgy doesn't care enough to do their own testing. IMR info may fall into the same boat with them...