Barnes 7mm Rem Mag 145 Gr LRX - how much jump is required?

[GMHVAC]

Developing a load for 145gr. I have been doing some research and it looks like a lot of folks are using a jump of about 0.050". That seems excessive as I usually have a jump of less than 0.020" for lead bullets. But with the Barnes being all copper does the jump need to be that much higher? My magazine is quite long so there is no restriction.

 

[stubblejumper]

Barnes recommends starting with .050". I am seating from .040" to .070" depending on the rifle. Seating monometal bullets close to the lands can result in much higher than expected pressures.

 

[todbartell]

.050 or so is a good place to start. More to do with the start pressure of the bullet than accuracy. Monometals have a higher start pressure than a lead core jacketed bullet, thus the longer jump to the lands to reduce that pressure increase

 

[hometownhero]

Let your gun be your guide in this journey. Only it can tell you how much jump to use.

 

[GMHVAC]

Awesome. Thanks for the feedback. I will start at 0.050 and see how it goes.