Reloading 9mm RN OAL has to be really short not to engage rifling??

[Para_au]

I have been reloading for about 6 months with Frontier CMJ 124gr round nose with 4.3gr of Win 231 with an OAL 1.150 in my Para P18.9 with very good results. I have just bought some Hawkesburry River Lead moly coated 125gr Round nose projectiles. But the problem I'm having is in order to chamber properly in my P18.9 the overall length needs to be a maximum of 1.080!! As this is considerably shorter I am a bit concerned about over pressure within the case. I know this is due to a different shape round nose projectile. But will this load 1 be safe and 2 be accurate?

[Nnobby45]

As long as your load is standard pressure and even a little below max, then I don't think 70 thousandths deeper is anything to worry about.

Don't know what load data you used. If you switched to lead bullets you should actually use lead bullet data, but you should be ok if you used the 4.3 gr. load.

If I were loading up around max, then I'd reduce a little for .07 deeper.

And for loading .40 cal. where deeper seating can raise pressures much quicker, I wouldn't go that much.

NOTE: A RN bullet loaded withing OAL spec shouldn't be engaging the rifling. I'd suspect the Moly coating. Do some experimenting with some loaded rounds using your barrel as a gage. Find out how long they can be and still plop right into the chamber and fall right out.

[Para_au]

Please see different projectiles 125gr lead moly on left and 124gr CMJ on right.