Shorter barrels and type of powder required

[duke1]

I just bought a gun with a 24" barrel and chambered in 30-06. I had it rebored to 35 Whelen and the barrel cut to 20".

My questions:

1. Should I look at faster burning powder to maintain best performance?

2. Would faster burning powder have any negative effects on the barrel?

3. Also before I look it up, are there any loading data for barrel lengths shorter than what is usually used for load development. Most loading data is based on 24" barrels or longer.

4. I will be pushing 225 & 250 gr. bullets so will the 225 work better than the 250 in a shorter barrel - that is under ideal conditions for each.

Thanks,

Duke1

 

[H4831]

1) You will require faster burning powder for the 35 Whelen, as compared to the 30-06, because of the larger bore for the gas from the burning powder to fill.

2) The powder that gives the best performance in the 35 Whelen with a 24 inch barrel, will also give the best performance in a 20 inch barrel.

 

[Scott_N]

I think the powder that gives you the best velocity in a long barrel is also going to give you the best velocity in a shorter barrel.

 

[Andy]

RL-15 and IMR-4064 will be hard to beat.

1) You will require faster burning powder for the 35 Whelen, as compared to the 30-06, because of the larger bore for the gas from the burning powder to fill.

2) The powder that gives the best performance in the 35 Whelen with a 24 inch barrel, will also give the best performance in a 20 inch barrel.

True - the idea that certain powders are tuned to certain barrel lengths just won't go away.

Often facts get distorted or misinterpreted.

More of a slower powder will produce a higher MV than less of a faster powder at the same peak pressure - makes sense as more powder = more energy. For the 35 Whelen, a full case of RL-15 on top of a 250gr bullet yields max SAAMI pressure for that round, so will produce the highest MV of any powder. You can use less of a faster powder, but won't get as high a MV, and if you use a full case of a slower powder, MV and pressure will decrease.

You will lose more MV per inch less of barrel with the slower powder, but you'll still have a higher MV at every barrel length than the faster powder.