Why are WC's seated so deeply?

S Mac

Sept. 10, 2021 Steve left us. You are missed.
In another thread about loading WC's several folks suggested using AC brass. I understand the reasoning behind that, but why can't they be seated less deeply than flush or nearly flush?
 

Brad

Benevolent Overlord and site owner
Staff member
I'm many they can. Some autoloaders designed for 38 wadcutters won't let you seat them beyond the case mouth but revolvers don't care.
I bet some of it comes from wanting lube grooves in the case and reduced case volume. Reducing case volume means less powder for the same pressure.
 

RicinYakima

High Steppes of Eastern Washington
Brad has the correct take on this subject. What we call full wadcutters were begun in the 1920's seated into the case. The earliest were seated to the same length as RN. Two things happen with deep seating: less powder, less recoil and you can load a bigger bullet. Wadcutters are commonly .360+ inches so the factory round is a snug fit into the chamber and not lying on the bottom of the chamber. When I was in LE in the '70's we would load WC's 1/2 out of the case with 5.5 grains of Unique. After a shooting, it was just practice ammo, forgot to put the RN's back into the revolver. HTH, Ric
 

S Mac

Sept. 10, 2021 Steve left us. You are missed.
Yes, it's a revolver I'm loading for. My point is using regular 38 Special brass, and not seating so deeply thereby not seating the base down in the process. I do understand it will change the pressure somewhat.
 

Brad

Benevolent Overlord and site owner
Staff member
Seated longer they can engage the cylinder throats and be held concentric by the throat. Should improve accuracy some.

No right or wrong answer, see what work for you gun. I often set them 1/3 out of the case.
 

fiver

Well-Known Member
you can leave the front drive band out of the case to mimic a SWC type bullet.
I generally load stuff like the 358091 the same as the 358477.
except I put more powder behind them for some reason.
 

358156 hp

At large, whereabouts unknown.
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RicinYakima

High Steppes of Eastern Washington
"I do understand it will change the pressure somewhat."
This is in error! Seating depth will change pressure GREATLY! Every 1% of decreased volume within the combustion chamber of the case, increases the pressure 4%. This is with DuPont single base powder, i.e. IMR. With Hercules double based powder it is even more! Read your manuals' listing of OAL for each load. This also applies to long seating WC"S, so consider what you are about. Where the base of the bullet sets in the case is very important.
 

fiver

Well-Known Member
at one time Alliant [Hercules] was DuPont. [IMR too]
DuPonts powder program got broke up under the US's monopoly laws, they had been steadily buying up the competition since the late 1800's.
the thing about it was they would have 'high scoring' [Basically pro.] shooters being used for their products but they made sure shooter-A was in Indiana while shooter B was in New York.
this way product A could use shooter A's high scores and his trophy's won, in their advertising.
and product B could show shooter B. having a separate long run score and his trophy's, in their advertising.


I found it interesting when they would tell a load and it was mentioned as ONLY 44grs of this or that in their trap loads.
 

S Mac

Sept. 10, 2021 Steve left us. You are missed.
Your caution is good advice Ric. My train of thought is with a lack of data for this particular mould is using data for a similar plain base mould. Would not the pressure be less with the hollow base, especially if it is seated a bit long?
 

Bret4207

At the casting bench in the sky. RIP Bret.
It also makes a difference if you're using hollow based or solid WC's obviously. I did a bit of experimenting with my M19 Smith and WC's some years (decades?) back based on something I read in Handloader by Al Miller IIRC. Sure enough, seating depth made all sorts of differences, some good, some not so good. I still prefer to seat my H+G 38 WC's out of the case mouth by 3/16" or so with a light crimp. Works nicely in my guns so far even if it does look a bit odd.

In the 32 S+W Long I used to shoot a lot of 32 S+W (short) brass and 90gr WC's that were longer than the case. Funny looking things but they worked fine and made a pound of powder last forever.
 

RicinYakima

High Steppes of Eastern Washington
Your caution is good advice Ric. My train of thought is with a lack of data for this particular mould is using data for a similar plain base mould. Would not the pressure be less with the hollow base, especially if it is seated a bit long?
Yes.
 

Pistolero

Well-Known Member
Hmm. I see a new testing batch coming up "one of these days".

I have done a good bit of fiddling with WC loads, and seating depth is about the only variable that I
have not explored. About time.

Bill