OAL for JHP bullets


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Austin Charles
December 29, 2004, 10:03 PM
Should I use a different OAL for JHP's as to jacketed bullets?

The reason I ask is I just got some Montana Gold 165gr JHP and they are longer than what I was using, 165gr (West Coast Bullets, RNFP)

I would tend to think that this will cause some higher pressure if I seat them at the same OAL as the FMJ.


My Speer #13 has Gold Dot JHP's in 165gr. Would I be ok using their load data? Speer alway's seems to be on the high side from everyone else.


I will be shooting these out of a Glock 27 & 23

If anyone has some favorite loads for the Montana Gold 165's JHP I would be grateful to hear them.

Thanks Erik

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stans
December 29, 2004, 10:24 PM
Actually you need to load to an OAL that is reliable in your firearm. Anytime you change bullets you should work up loads again.

Austin Charles
December 29, 2004, 11:34 PM
Yea, I am going to have to anyway because the West Coast bullets use lead data.

I guess my question is can I use FMJ data for JHP's? and will the Speer Gold Dot load data work?

Thanks Erik

stans
December 30, 2004, 07:21 AM
Plated bullets generally follow load data for cast lead. Plated bullets are nothing more than swaged lead bullets with a thin copper plating. This gives them a hardness that is fairly close to a cast lead bullet. Jacketed bullets using traditional copper jackets are harder than plated or any lead bullet, so the load data is different and it takes more powder to push a jacketed bullet to the same velocity as a lead or plated bullet.

You might be able to use the exact load data for a 230 grain FMJ load with a 230 grain JHP if the bases of the bullets are seated to the same depth in the case and the bearing surfaces of the bullets are identical. If the JHP bullet has a longer bearing surface (the total surface of the bullet that contacts the barrel grooves) then it will have more friction in the barrel and will not be propelled quite as fast.

Seating a JHP so that the base of the bullet is at the same depth as a FMJ bullet could result in a round that is too long in OAL to function in your firearm. When a JHP is made, the lead that is displaced by the hollow cavity has to go somewhere, so JHP bullets tend to be a bit longer than FMJ bullets of the same weight.

I still think that it is safest to work up a new load when switching bullets.

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