26 inch barrel vs 28 inch barrel

[Country boy]

I have a 338 rum loaded with 180 grain accubond loaded with IMr 7828 101 grains and I am thinking of replacing the factory 26 inch barrel with a custom 28 inch barrel made by hart with no muzzle brake can anyone tell me how much velocity I could gain if any . Im new first time posting so pls be easy guys any info would help thanks

 

[J E Custom]

I have a 338 rum loaded with 180 grain accubond loaded with IMr 7828 101 grains and I am thinking of replacing the factory 26 inch barrel with a custom 28 inch barrel made by hart with no muzzle brake can anyone tell me how much velocity I could gain if any . Im new first time posting so pls be easy guys any info would help thanks

50 to 100ft/sec.

J E CUSTOM

 

[Country boy]

K thanks