Switching from 9mm RN to FP.. What to do with my OAL?

[taymag]

I load at 1.100" with 147gr RN, I think this is a little short so I don't know where to go with my new FP I am switching to. 1.142 is the load data for RN on the powder companies website but they have 1.142 for HP too which I assume is more like a FP.

I thought FP was was going to load shorter?

BTW the new bullets are 147 9mm Acme FP

 

[Blue68f100]

FN should not be that much different from a RN. HP are normally longer since the base is deeper.

I always find a OAL that works in my gun, then work the load up from there. Mfg data, is just what they did with there test chamber/gun. Some guns like shorter other longer. I like to run the longest I can.

 

[Sunray]

An HP is a Flat Point. 1.169" is the OAL given by Hodgdon for all 147 grain bullet (except the XTP's for who knows why.) including a cast 147's.

 

[Dudedog]

Plunk test to determine the longest OAL you can use (search plunk test, Walkalong has a excellent post about it)
the adjust for feeding if necessary.
I have more than one 9mm so I usually load for the shortest one.

 

[Dudedog]

Plunk test to determine your OAL
https://www.thehighroad.org/index.p...rel-find-a-max-o-a-l-with-your-bullet.506678/

 

[snakeye]

I don't know what brand bullets you are using but typically my Xtreme 124gr FPs are shorter than the RN and are loaded shorter than the RN. I take measurements of each new bullet I use and log them in my logbook. The Extreme 124gr RN is .585 and the FP is .525 considerably shorter. My records indicate the HPs ( XTPs and Precision Delta) I use are at .575 and .585 respectively.

I would measure both bullets and find the difference in length and that should help drive you in the right path of a load and length you need to run

 

[Walkalong]

I load at 1.100" with 147gr RN, I think this is a little short so I don't know where to go with my new FP I am switching to. 1.142 is the load data for RN on the powder companies website but they have 1.142 for HP too which I assume is more like a FP.

1.100 is pretty short with a 147 Gr RN.

1.142 is kind of long for a FP or HP, which load shorter than most RN bullets.

I load various 9MM RN bullets at 1.130 to 1.135 or 1.140 to 1.145 OAL.

Is the new FP a 147? If so, and your old load is safe, as long as you don't seat the new 147 deeper you will be OK. Not how long, but how deep is it seated. Same goes for whatever data you use, how deep is your bullet in the case compared to the one used in the data.

 

[deadeye dick]

Like Walkalong says. I load my 147 lead at 1.130 1.135 also. RNFP's at 1.150. Works for me.

 

[rfwobbly]

1.100 is pretty short with a 147 Gr RN. [snip] Not how long, but how deep is it seated. Same goes for whatever data you use, how deep is your bullet in the case compared to the one used in the data.

Your Max OAL is set by the gun's chamber, or more precisely the distance from the bolt face to the lands.
Your Min OAL is set by your brand of brass.

You must be using a single brand of brass with extremely thin walls to seat 147gr bullets to 1.100" OAL. Most 9x19 Luger brass won't accept bullets seated deeper than ~0.25" and some brands only ~0.20". This because the case wall thickness starts to increases at mid-case. If you seat the bullet past this point, the case starts to imperceptibly bulge in the middle making it impossible to chamber.

To see this all you need to do is set your caliper to 0.355" and slide the "inside" tines into a cartridge case. It's amazingly shallow.
.

 

[peels]

As others have said, the Max COL is set by the combination of the bullet profile and your gun. Not all hollow point have the same profile as a flat nose bullet. Case in point are Gold Dot (tm) hollow points. These bullets have more curved nose profiles that are typical of a round nose bullet (but with a hollow point). Typical target based hollow points and flat points have a simple conical shape and they engage the barrel lands differently. Your bullet profile appears to be conical shaped.

Some gun barrels (CZs, for instance) require much shorter COL when using conical HP or FP profiles in order to chamber properly. And thus it is important to make sure YOUR loads chambers in your guns properly. It is a good practice to find the absolute max COL of any new bullets in your gun(s). Load a dummy round and seat the bullet way long. Perform the plunk test in your gun's barrels. Keep reducing the COL by 2 thousandths until it passes the plunk test. Record that COL as your absolute max COL to not exceed. You typically would want to be at least 10 thousandths below that absolute max just in case with variations in COL and nose profiles from round to round.

If the load recipe's COL is 10 thousandths less than this absolute max COL, then just use the recipe's COL. If it is longer...then proceed with caution. When you load to a COL that is shorter than what the recipe calls for, your loads may result in higher pressure.

Good luck and be safe!