18" 300wsm Powder??

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WKR
Joined
Jun 13, 2017
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Anybody have a powder recomendatuon for a 300wsm with an 18inch barrel shooting 165 to 180 grain bullets? I am new to the short barrel world and trying to get the best velocity.

Thanks for the insight.
 
Dang that is a lot of information. Now I just need to educate myself on what the important stuff is and what I can ignore.

Thanks a bunch!
You're welcome, and pressure is the first thing you'll want to consider. This tool is a guideline, and every rifle will express pressure slightly differently in the real world. This load should be considered a "max" load given the top of the pressure curve resting at maximum SAAMI pressure. However, this tool isn't perfect, and you will need to work up your load based on observations working up to this theoretical max.

The cartridge length (bullet seating depth) can also impact pressure significantly for a given poweder/bullet combination. The default for this tool is the SAAMI cartridge length, but often guys will seat bullets out beyond SAAMI length, and this can reduce pressure, thereby increasing available capacity before hitting max pressure.
 
You're welcome, and pressure is the first thing you'll want to consider. This tool is a guideline, and every rifle will express pressure slightly differently in the real world. This load should be considered a "max" load given the top of the pressure curve resting at maximum SAMMI pressure. However, this tool isn't perfect, and you will need to work up your load based on observations working up to this theoretical max.
Sounds good. I am a very conservative reloader. Something about over 60,000 pounds of pressure that makes me take it serious!
 
Smith just told me my 18” wsm is ready. Hope to work up a load for the 180EH or 185Juggs
 
Gordon’s is a good tool, but you have to be very careful with it. Results from it can vary wildly, and some of the powder models are not very good. They stopped updating it when he died, so it’s missing all the newer stuff. Cartridges and bullets are fairly easy to add, powder not so much.

The variability of the program is well evidenced by what happens when you copy recipes from published reloading manuals. A published load might be right on the money in the sim, but I’ve also frequently seen them vary from 40ksi all the way up to 80ksi in the sim. Things like measured
case capacity, bullet initial pressure, boat tail length, etc can all impact the sim. A bullet initial pressure change (from one standard value to another) can bump the sim 3ksi. Ditto on a grain or two of case capacity difference.

I like to start my load dev for Gordon’s data around what they list as a 44ksi load, and work up from there. That leaves plenty of overhead.
 
Gordon’s is a good tool, but you have to be very careful with it. Results from it can vary wildly, and some of the powder models are not very good. They stopped updating it when he died, so it’s missing all the newer stuff. Cartridges and bullets are fairly easy to add, powder not so much.

The variability of the program is well evidenced by what happens when you copy recipes from published reloading manuals. A published load might be right on the money in the sim, but I’ve also frequently seen them vary from 40ksi all the way up to 80ksi in the sim. Things like measured
case capacity, bullet initial pressure, boat tail length, etc can all impact the sim. A bullet initial pressure change (from one standard value to another) can bump the sim 3ksi. Ditto on a grain or two of case capacity difference.

I like to start my load dev for Gordon’s data around what they list as a 44ksi load, and work up from there. That leaves plenty of overhead.
Agree 100% and I also found discrepancies between the tool and reality for my 7-08 loads. It does pretty well for powders with lots of examples and data, but like you said, one should compare to other book data like any responsible reloader.

In expert mode you have the ability to create load dev ladders which is nice, and the more steps you add, the more conservative it starts. Here's an example where I selected a 10 step ladder with .5 grain increments. The load data and relative pressures are listed above the graph with representative pressure curves in the graph.

1745326389340.png
 
Yeah, I like to do the 10 ladder and skip every other for the first few. Normally I’ll only load one each at the lower pressures, but it’s a good sanity check, especially for loads that vary greatly from similar published data.

Hogdon has great published online data, as does Nosler, Berger, and many of the other smaller bullet manufacturers. For a common SAAMI cartridge like the WSM, I’d start there first. If the OP plans to load long and has a chamber that supports it, Gordons could be really helpful to adjust the data for the extra COAL.

Here’s the thing with loading long in a WSM. It works really well with heavy bullets, which is where SAAMI WSM load data really starts to fall behind the 300 Win Mag. For bullets 180 grains and less, it may not help much at all, as a SAAMI length cartridge may have the bullet seated mostly out of the powder column with the lighter/shorter bullets in the 150-180gr range. 180grs or so seems to be the crossover point where seating longer starts to help.

Loading long without a powder that supports it may actually drop muzzle velocity. Extra case capacity is only useful if you have a powder that benefits from adding more before pressuring out. With a longer COAL, and thus more powder capacity, you actually HAVE to add powder just to hit the same pressure/velocity as the shorter COAL with less powder. For some bullet/powder combos this really pays off. For others it buys nothing, or can actually hurt.

For powder, I’d look at H4350 first, since it’s very temp stable and easy to find. You may give up a few fps vs a Reloder powder, but I’d much rather have something simple and easy to find.

Check out the reviews on Norma’s 180gr bondstrike factory loads also. Seems to be a very good factory load for a good price, and you make great reloading brass while shooting it.
 
I would focus on 100% burn out before the barrel. You will see lots of inconsistencies with your barrel burning less than 100% (I have first hand experience with a 20” barrel). If you’re using GRT (highly recommended it), play around with it you should input all of your parameters and be very meticulous about it to calibrate the software. Like others have said, it’s not 100% foolproof, but it’s pretty effin good.
If you’re worried about pressure measure your case-head (there are videos on YouTube) and make sure it doesn’t exceed half a thousandth of an inch. This is a good indicator for safe pressure. Make sure to measure virgin case and then your fired cases. Get a 1” 1:10000” micrometer (on Amazon they’re like $50CAD, so like $3 American), keep track of these cases and measurement, and work your way up. This is the only way to actually track your pressure, everything else is theoretical! DM if you got questions!
 
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