Increasing oal

[dajowi]

I'm currently loading a 147 Gr. FP hard cast bullet in 9mm. The reload data suggests a OAL of 1.058". I've been shooting a 115 Gr. FMJ with a maximum OAL of 1.104". Both of these functioned in the gun.

Would anything untoward happen if I increased the OAL of the 147 Gr. cartridges to an OAL of 1.104? Does this effect the pressure?

 

[PA-Joe]

The FPs will contact the lands if you use the RN bullet data. Yes, this will increase the pressure and they may not feed correctly in the first place.

 

[OEF-Vet]

Increasing the OAL does affect pressure in fact it lowers it, so as long as the bullet is seated properly and the round feeds properly it should be a non-issue. However any velocity and energy calculations will also be reduced a minuscule amount.

 

[89blazin]

oal

If the FPs do not make contact with the lands when chambered, the pressure will be reduced. Make a test FP bullet at the longer OAL w/ no powder or primer and see if it chambers as normal.

 

[OEF-Vet]

I second 89blazin's approach of a dummy round. I didn't factor the bullet reaching the lands in less the 5/1000 of an inch in my previous post but it is possible.