Too high of velocity, 10% higher than published data

[NATJAC]

Hi, sorry, not sure where to post this.
Got a question, i've cast up and powder coated 1000+ 9mm hollow point boolits (mp mold) that weigh right around 130 grains.. I'm using WSF powder, which only has data for 124 cast boolits.. I used that data and started at the minimum of 4.0 grains (4.7 grains is the max with a published velocity of ~1055 pfs) I couldn't get any accuracy (and clean brass from sooting) until I got to 4.7 grains.. the 4.7 grains is great for accuracy and clean brass, BUT, my chrono is showing almost 1200 fps! which is over 10% faster than max published data!! I don't have any signs of overpressure such as flattened primer or anything else odd. I want to load up over 500 rounds of this load but I figured I'd check with the seasoned veterans to see if they'd warn me not to do it. Also, as you may know there is a powder shortage so it's not like I can go out and find another powder.. and I would like to simplify and use WSF for many other calibers including shotgun. The WSF shoots great in 9mm, really like this powder, just not sure why they don't have any good published data for anything OVER 125 grains, why is that?
Let me know your thoughts.

[Mk42gunner]

I haven't loaded any 9mm for about twenty five years, so these are going to be general comments. I've also never burned any WSF powder.

Heavier projectile with the same powder charge may generate higher pressures, and thus higher velocity. It may not either.

Your powder coating may affect velocity/ pressure also.

Barrel length. You didn't say what you are shooting these out of, so if the data you are looking at used a four inch barrel and yours is closer to five...

Good Luck,

Robert

[44Blam]

One thing to consider is that you are casting a hollow point. So, that boolit WEIGHS 130 grain but if it was a round or flat nose it might be like a 135 or 140 grain boolit. That's the load data you want with a HP. We kind of get fixated on weight of the boolit but the load data is really based on case capacity with a boolit seated. So if you have the same boolit at max col vs one a couple hundreths deeper the one a little deeper will generally have higher pressure. The grain weight kind of gives us a general idea of where the boolit is going to sit in the case, so we use that as a starting point...

[wv109323]

The type of firearm or testing fixture could make a difference. Bore diameter,barrel length,temperature chrono accuracy and bullet coating can all enter into the final velocity.
I would do more research and maybe call the powder manufacturer.

[JoeJames]

Something else to throw into the mix. I have found in shooting hard cast (water quenched) vs. air cooled of the same alloy that my Lee .430” 240 grain swc’s run about 80 to 90 fps faster if water quenched.

[JimB..]

Are you loading them as long as possible for your pistol? If not, give it a try and see if you can come off the charge a bit and retain accuracy.

I wouldn’t worry about soot on pistol cases, especially for shooting paper.

[44MAG#1]

My questions are:
1. Are you using the same "lot" of powder as the lab?
2. Are you using the same brand and "lot" of primers that the
lab used?
3. Are you using the exact same bullet that the lab used?
4. Does your bullet seat the exact same depth in the case?
5. Are you using the exact same brand of cases and if you are
are you using the same "lot" of cases?
6. Are you testing conditions the same as the lab had?
I predict you will get a plethora of answers by everyone from those that have little experience to those that have thousands of dollars of equipment and more firearms than the US Military.
Just chose who you want to listen too.
Myself, if I were concerned I would drop back on charge weight, load and have fun. If not concerned I would load and have fun.
You will have to make that call.

[JonB_in_Glencoe]

Are you loading for semi-auto pistol?
Many times when working up loads, besides accuracy, I judge a load by how far the gun throws the spent cases. I'd be less concerned about FPS, as long as you aren't seeing signs of over pressure or launching the brass into the next zip code.

[PonchoHobbes]

One other possibility could be the load data itself if it's form just one source. I have probably 5 different loading manuals plus all the online options and none of them agree but they do give a consensus of an approximate range. I was loading for 45 Colt last week and the max charges for Unique with a 250 grain cast bullet were from 7 to 9.5 grains and advertised velocity was between 850-950 fps.

Sent from my Pixel XL using Tapatalk

[GARD72977]

I say load away. You are within published data and not showing pressure signs. Some barrells are faster than others. The powder coat could account for some increase.

I would be aware as the summet temps increase.

[chutesnreloads]

Not all chronographs agree with each other. Are you sure yours was set up correctly? Just a slightly shorter or longer distance between the "eyes"
will make a much bigger velocity reading. Suggest you try a few more after setting up chrony again. Also.... How many rounds of this load did you fire through the chrony?

[MT Gianni]

Looking in Hogdsons data center max for 124 gr is 4.7 max for 147 is 4.1 gr. I would cut it back some at least until the velocity approaches the listed 1088 fps.

[jim147]

I don't see what size you are using. And have you slugged the barrel? I would think if the boolits are too small, you would need to push them harder to seal up.

That's my thought at the moment but I've been sick for two weeks and woke up at 3:30 this morning so I could be wrong.

[NATJAC]

The Barrel length is 3.5", the load data, which is from Winchester's webpage, uses a 4" barrel for testing. They are using CCI-500 primers and I'm using WSP primers.

[NATJAC]

Are you loading for semi-auto pistol?
Many times when working up loads, besides accuracy, I judge a load by how far the gun throws the spent cases. I'd be less concerned about FPS, as long as you aren't seeing signs of over pressure or launching the brass into the next zip code.

Yes both semiauto, a g19 and MP9c
From 4.3 to 4.7, all of the cases landed in the same spot, roughly.

[NATJAC]

Not all chronographs agree with each other. Are you sure yours was set up correctly? Just a slightly shorter or longer distance between the "eyes"
will make a much bigger velocity reading. Suggest you try a few more after setting up chrony again. Also.... How many rounds of this load did you fire through the chrony?

This is kinda what i'm thinking.. I've shot these before with the only difference being a different lot of powder and those were right in line with the published FPS.
I fired 8 rounds of each increment:
8ea 4.0gr, 8ea 4.4gr, 8ea 4.7 thru two different handguns (g19 and MP9c)

[NATJAC]

I say load away. You are within published data and not showing pressure signs. Some barrells are faster than others. The powder coat could account for some increase.

I would be aware as the summet temps increase.

I've looked in all the manuals I have for loads, none really showed anything for WSF and 9mm except for the Lee book and Hodgdon website (which are the same load data)

[NATJAC]

One thing to consider is that you are casting a hollow point. So, that boolit WEIGHS 130 grain but if it was a round or flat nose it might be like a 135 or 140 grain boolit. That's the load data you want with a HP. We kind of get fixated on weight of the boolit but the load data is really based on case capacity with a boolit seated. So if you have the same boolit at max col vs one a couple hundreths deeper the one a little deeper will generally have higher pressure. The grain weight kind of gives us a general idea of where the boolit is going to sit in the case, so we use that as a starting point...

You are correct, this is a HP bullet and the net weight of the boolit is ~130 grains. So you are saying that I should look for load data for ~135-140 grains?
I had to seat these to a COAL of 1.11", otherwise the boolits would touch the lands.

[NATJAC]

These are air cooled. ~ 8 bhn

[Driver man]

I think powder coating affects chamber pressure. i have had similar results to you .