Precision Delta OAL???

[leadchucker]

I'm trying to figure up a starting point for loading with Precision Delta 9mm 124 gr FMJ RN bullets. The load data for a Sierra 125gr FMJ RN 8120, in the Hodgdon manual would seem to be a fairly close match.

The Hodgdon data calls for an OAL of 1.090 for the Sierra bullet. According to the Sierra data, the Sierra bullet is .581 long. That's about .020 shorter than the Precision Delta bullet. So I'm looking at an OAL of 1.110, but that OAL puts my Precision Delta bullet in so deep it's past its ogive.

That also figures out to be a seating depth of about .250. That's kinda deep ain't it?

So I figure I'm going to have to increase OAL. Right? What I'm wondering is what is a good average minimum seating depth for a 9mm bullet? (assuming no issues with magazine fit/feeding/plunk test.)

[delta tide]

Using this same bullet, I started trying what I thought was a conservative OAL at 1.140", but I kept getting bullet set back when cycling the dummy rounds. Lack of grip from the case, maybe? I extended the OAL out to 1.150", and this cured the set back problem. After testing live rounds at the range, I got a better accuracy results out of 1.160". This seemed long, but it was still under the max of 1.169", and my M&P9 and M&P9c have no problems cycling the cartridge with this OAL.

I just ran out of the 124gn FMJs, gonna experiment with the 124gn JHPs next (back ordered).

[Xfire68]

I just ran some DP 124g JHP's the other day at the range. I was testing out some Tight Group at 4.2g. They were accurate and cycled great but the primers were cratered. The loads with 4.0g's did not show any signs of high pressure.

The OAL was 1.065 for both.

I am testing 4.0g's of Bullseye next.

My most accurate load out of my CZ 75B was 7.0g's of Power Pistol using a 90g XTP. From a rest I was getting same hole accuracy at 25 yards. Yes that is a hot load but, zero signs of over pressure while firing those.

Another load I loved was using AA #5 but, I ran out of that powder and I have too many different powders as it is. I am trying to find 4-5 powders that will work relatively well with all of the calibers I shoot.

Power Pistol, Unique, H335, H110 and Herco seem to be what I am trying to live with? I did just buy some 800x to try in the 10mm. I hear that it is the secret to true 10mm loads? Ok I have rambled on way to long! Sorry.

[adamc]

still waiting for my Delta order......

[showmebob]

I've been using a COL of 1.135 with P.D. 124 gr round nose without any issues.

[leadchucker]

I've been using a COL of 1.135 with P.D. 124 gr round nose without any issues.

After blowing all day fretting over this, I'm thinking that sounds like a good starting point. That gets the bullet ogive outside the lip of the case, and doesn't make for feeding/chambering problems. I just wanted some logical justification for deviating from the reference round I was using.

Looking at all the loads I've done previously, and at a lot more loads in load manuals, I discovered something interesting. The seating depth on most FMJ pistol rounds is around one half of the bullet diameter. A few, like this example in the Hodgdon manual, seat significantly deeper, but very few seat less than that.