38 wadcutter accuracy per seating depth

[BJung]

I have always seated my 38 -148 wadcutters to the first lube groove. I've also seen photos of the bullet seating flush with the case mouth.

Has anyone ever seated the 148 wadcutter farther? Did you find an improvement in accuracy?

[FITASC]

I seat them flush; my Hornady do not have lube grooves.

[USSR]

burbank_jung,

I seat my HBWC's flush (1.18") and my flatbase wadcutters out to the crimp groove. Hopefully next year I will do extensive testing with my Ransom Rest.

Don

[rodfac]

Interesting question. In my use (Lyman's 358091 WC), I've found that seating out, has a bit more accuracy. I'm guessing that the exposed lead helps to align the bullet, in the cylinder throat, as it leaves the case. I have a number of .357 guns, and this is true for all of them.

As the chamber on a .357 is longer by roughly a 1/8", and I'm shooting .38 special loads put up in .38 special length brass, that add'l jump to the cylinder throat may have an effect on alignment. 358091 is a bevel base design and has three lube grooves with one crimping groove and maybe 1/10" of lead exposed above the crimp groove, BTW.

As to accuracy, the effect is only visible at 25 yds, from a rest, and is less than 1/4" in group size....which might well be accounted for by alloy, amount of lube used, casting flaws, case neck tension...you get the idea. In use, from an offhand position, the difference, if any, is negligible.

Hope that helps...but probably just further muddies the waters. Rod

[BJung]

rodhac. I shoot my .38 brass out of a .357. So maybe it's possible to seat the wadcutter out 1/8"? Has anyone does this before? I suppose I'd have to change my load data slightly?

[74A95]

Originally Posted by burbank_jung

I shoot my .38 brass out of a .357. So maybe it's possible to seat the wadcutter out 1/8"? Has anyone does this before?

yes. this is nothing new.

Originally Posted by burbank_jung

I shoot my .38 brass out of a .357. So maybe it's possible to seat the wadcutter out 1/8"? Has anyone does this before? I suppose I'd have to change my load data slightly?

you'll need to add more powder if you want the same velocity as flush-seated bullets.

[BJung]

Can I load my COAL flush to my cylinder? I never noticed the length, having seated allhe bullets to the cannelure or gas groove. Is there a noticeable improvement of accuracy?

[USSR]

That's not gonna leave much bullet in the case - I wouldn't do it. You're worrying too much about seating them out. The Bullseye shooters shot record scores with them well into the case in years past.

Don

[BJung]

Okay, good to know. If the Bullseye Shooters do well with them seated in, I'll do the same. Thanks.

[rodfac]

The only drawback to using .38 Spl brass in a .357 is the crud ring build up at the front of the chamber. I do it all the time but I do cleanout my chambers after firing...and seldom shoot more than a box of 50 at one range session.

As to seating the bullet out a bit...again I see no harm so long as you have sufficient shank depth within the case for good powder burn. Bullseye powder takes very little neck tension to burn efficiently and is the gold standard as far as super accurate range/competition in Bullseye NRA use. You'd have to try it in a controlled test to determine which method works best for you.

Rod

[BJung]

OK thanks. I'll try a few test loads and seat to the next gas groove and and see if it makes a difference.

[jetinteriorguy]

On DEWC’s I seat all the way to the second crimp groove so just a little of the bullet extends beyond the case in .38sp cases. I shoot two different loads this way 2.8gr of BE and 3.1gr of BE. HBWC’s are seated so they just protrude slightly, these I shoot with 2.8gr of BE only.

[BJung]

Why do you have two loads? 2.8gr BE and 3.1gr BE? Curious

[T. O'Heir]

148 grain WC's are supposed to be seated flush with the case mouth with no crimp. 1.160" COAL. Mind you, you can load .357 cases to .38 velocities with no fuss too. 1.290" COAL. Makes the lube crud ring go away.
DE WC's are seated to the shoulder.
"...do not have lube grooves...." Likely swaged. No grooves in swaged bullets. Lubed with graphite. They're made literally by squeezing soft lead wire into shape. Swaged WC's are fabulous things so they are.

[USSR]

Why do you have two loads? 2.8gr BE and 3.1gr BE? Curious

I imagine it's because in the one load the wadcutter is seated nearly flush, and the other one is seated out a bit. You need a "titch" (technical term) more powder when seating the bullets out to reach the same velocity/pressure.

Don

[Unclenick]

Originally Posted by burbank jung

Why do you have two loads? 2.8gr BE and 3.1gr BE? Curious

I believe he's using the larger charge when the bullet is seated further out. Seating a bullet further out makes more powder space, so it tends to lower both peak pressure and rate of growth in pressure. That can result in larger velocity spread and less consistent ignition. Inconsistent ignition can result in irregular delays. It's sort of like having your gun's lock time vary with every shot, making it require more perfect follow-through to avoid groups growing.

A caveat is that at least one load (hp-38/231) in the Hodgdon data uses smaller charges for wadcutters in 357 cases than in 38 Special. I emailed them about it and all they could say was this is what their ballistic tech had certified was how they behaved. My working theory is the shorter powder space caused the primer to unseat the bullet in the 38 Special but not in the 357, resulting in the powder space being larger near the peak with the 38 Special. This situation did not obtain for other powders, though Titegroup has the same maximum listed for both cases. It's one of the oddball things that can happen that you have to watch out for. It's reasonable to assume more space means more powder is requires, but test and use a chronograph to be sure. If velocity is lower in the larger case, then more powder is need. But if it is higher in the larger case, you want to back off the load some.

Seating wadcutters out in the .357 chamber makes sense to do. When the bullet has to jump too far to the throat, a fair amount of gas can leak out around the bullet before it gets to the narrow part of the throat. That can also interferes with pressure rise to introduce lower velocity and longer barrel time and it also allows more opportunity for gas cutting of the bullet base. All those things tend to reduce accuracy. Note that seating flush in 357 brass may get you close enough to the throat if doing it in a 38 Special case does not.

[Hanshi]

I load all HBWC flush, and SBWC to the top groove.

[jetinteriorguy]

Originally Posted by burbank_jung

Why do you have two loads? 2.8gr BE and 3.1gr BE? Curious

I’ve found the heavier load works better for DEWC but the lighter load works better for HBWC.

[Unclenick]

That may be because the heavier load has more intrinsic accuracy, but creates some skirt blow-out with the hollow base bullet. Powder space with the two is the same, as the space taken up by the HB's greater length is put back by the hollow in its base. If that were not true, given the alloy is the same and thus the same density, its weight would not match the DE version's.

[jetinteriorguy]

Originally Posted by Unclenick

That may be because the heavier load has more intrinsic accuracy, but creates some skirt blow-out with the hollow base bullet. Powder space with the two is the same, as the space taken up by the HB's greater length is put back by the hollow in its base. If that were not true, given the alloy is the same and thus the same density, its weight would not match the DE version's.

Yup.

[BJung]

If possible, wouldn't loading a cartridge flush with the cylinder create a more accurate bullet than one flush with the case length?

[USSR]

burbank,

You're obsessing over this. When .38 wadcutter ammo loaded flush with the case mouth for Bullseye competition can be fired into 2" at 50 yards from a Ransom Rest, how much more do you really need? Why not test it yourself by loading some flush and some loaded long? Just remember to use a little more powder for those loaded long.

Don

[Unclenick]

It can be so, but also depends on the effect of increasing the powder space on powder ignition. One thing well known about shooting lead through revolvers is that uniform diameter cylinder throats with bullets sized to that diameter or a half a thousandth less, tend to be most accurate. Having the bullet bearing surface (the full diameter cylindrical part) have little or no jump to start into the lands helps prevent gas cutting. This is another argument for using the brass the chamber is cut for.

[BJung]

USSR. It's just the tinkerer in me. I can't get to the range often so I like to ask. The outdoor range I go to is 80 miles away and costs $18 all day. I get free lead there too. The other closest range is 37 miles away and costs $30 for 3 hours. No free lead. Plus I have a lot of test loads so I like the first choice. My mom lives up that way too so I usually stop by to say hi.

[BJung]

Uncle Nick. What does "using the brass the chamber was cut for?