Difference in Speed

[morgaj1]

I have been reloading for years, but only recently bought a chronograph when I took up long range shooting. I have 3 Tikkas (7mm-08, 30-06 and 300WM). All are consistently 100fps slower than the Nosler and Sierra manuals for a given load, regardless of powder. Why is that? I noticed that Sierra uses 26" barrels for testing. Is that the reason?

 

[jd5521]

If your barrels are shorter than what the test barrels show to be then yes. You will have slower velocities pending you are using the same loads as the manual calls for. By how much? That is determined I. The length of your barrels.

 

[morgaj1]

If your barrels are shorter than what the test barrels show to be then yes. You will have slower velocities pending you are using the same loads as the manual calls for. By how much? That is determined I. The length of your barrels.

My barrels are 2-4" shorter than the Sierra test barrels.

 

[jd5521]

Then Yes you will have slower velocities than those posted in the manual using the same charge.

 

[Tiny Tim]

Depending on caliber, you will generally lose 20-50 fps per inch of barrel shorter than one used for the manual.

 

[just_jon]

Accurate published this data on effects of barrel length on spee.

The Effects Of Reducing The Barrel Length On Velocity And Accuracy In The 223 Remington

 

[McHaggis]

And Tikka's are often reported as having slow barrels compared to most others. 100 FPS is common. Typically very accurate tho. Plus having a shorter barrel just adds to it.