9mm 90 gr. XTP load?

[Rule3]

I keep reading "start from min and work up" posted here. I really don't believe that is the case with most powders. I was taught, and most powder manufacturers state, "start at 10% below max and work up". Of course with a few powders the min is greater than 90% of max, H110 comes to mind. But the general rule I have always followed is start at 90% of max unless 90% of max is less than the listed min. And of course always work up incrementally. With the exception of HBWC, I can't think of that many loads that are more accurate or reliable at the min charge. Most min charges for handguns are the lowest charge that will reliably cycle the action.

Pretty much the same thing. Most start or Min charge are just 10% less than Max. or just take 90% of the max. Fun with numbers!

I can show all kinds of tested printed data that far exceeds the Hodgdon 3% rule .

 

[EVO]

How come I can't view page 2 on my iPad or phone

Oops, it was saying page 1 of 2 but looks like there was only 1

 

[Mad Chemist]

Depends on the load guide. Alliant, Speer and VV usually list starting loads at 90% of max. Ramshot and AA are all over the place with the min usually being the minimal functioning charge, at least for their pistol data. IMR, Win, and Hogdon have some loads that follow the 10% rule, with others showing a very broad range sometimes >25%.

To me, loads under 10% of max usually indicate a reduced load. I only work up loads below 10% of max if my goal is a softer reduced load.

 

[EVO]

My original question was on the win 231 powder because I could reference it in multiple books but I have other powders, do any of these typically have better results for this lighter bullet - autocomp, titegroup, universal, or hp-38.

 

[Mad Chemist]

I believe Win uses autocomp in their factory SD loads for .380. Data chart gives good velocity and it is supposed to meter well. I'm still on the lookout for some of this to work up some .380 loads with. Unique has given good performance but it does not meter well at the volumes used for .380acp.

 

[gamestalker]

I don't load light target powders at all, so most all of my experience has been with full tilt powders. So with the 90 gr. XTP and all other jacketed bullets for 9mm I use Longshot or HS6, but usually Longshot. They perform flawlessly and have been worked up to full maximum published charges.

As for how much to reduce, if the data I'm using is published with a start and max in the table, I simply use the start charge as a reference point. But depending on the powder used, backing off 10% isn't always what I do. Some powders, such as Longshot don't perform well and have experienced cycling issues when reduced that much. With a powder like 231 I would most certainly take a max charge down 8% - 10% and then work up in reasonable increments. Especially so with a high pressure cartridge such as the 9mm.

When I used those 90 gr. XTP's for the first time, I was concerned about the very small amount of bullet in the case, thus creating a possible neck tension issue. But after running 50 or so through my firearms, I didn't identify any such problems, what so ever. I even cycled several magazines in an attempt to try and create a set back scenario, all were fine. BTW, I don't bell or crimp the mouths, I just evenly chamfer the mouths, and then seat, this assures I will obtain maximum neck tension.

GS

 

[EVO]

So I made a few rounds and went to the range yesterday. First I tried the 90gn xtp with 5.7gn of autocomp which is the starting powder charge with OAL of 1.095 and the result was FTE, a blackened case and something spraying back in my face. So I tried 6.0gn of autocomp same OAL and same result. My hornady book says max load of 6.8gn of autocomp with OAL of 1.07, so my question is should I just keep adding more powder til it feeds correct and what was hitting me in the face? I went with the OAL of 1.095 because I started the plunk test and kept seating deeper til it looked good and that it where it ended up, should I use the 1.07 that hornady suggests.

 

[gamestalker]

I don't have my books in front of me right now, but what I would probably try doing is seat them at the published oal Hornady has, what ever that is, I think 1.090" don't take my word for that oal, verify first. Then start your powder work up from just below mid table at that oal. Though I rarely use published oal's, you might want to try this, because this is the oal Hornady tested them at.

It's possible that due to the extremely light weight and short bullet profile, pressures might not be able to peak long enough to fully cycle the action. This could be why I've had such flawless results with a full charge of slow powder like Longshot?

GS

 

[Rule3]

So I made a few rounds and went to the range yesterday. First I tried the 90gn xtp with 5.7gn of autocomp which is the starting powder charge with OAL of 1.095 and the result was FTE, a blackened case and something spraying back in my face. So I tried 6.0gn of autocomp same OAL and same result. My hornady book says max load of 6.8gn of autocomp with OAL of 1.07, so my question is should I just keep adding more powder til it feeds correct and what was hitting me in the face? I went with the OAL of 1.095 because I started the plunk test and kept seating deeper til it looked good and that it where it ended up, should I use the 1.07 that hornady suggests.

Post #8 We already gave you the COL whay do you want to seat it at some other length??

You also have the powder charge range of 5.7 up to 6.8 gr of Auto Comp

They test and publish this data for a reason.

You have a bullet seated to long and a bottom powder charge which is probably close to giving you a squib .