S&W Shield Bore Diameter?

[Michael J. Spangler]

I just slugged my s&w shield in .40
I came up with .4020 to .4023 diameter.
It's a 5 groove so I had to balance on opposing edges of the engraved slug.
Does this sound normal? Does anyone else have a .40 shield that they have experienced this with?
Thanks in advance guys. Looks like my mold drops around .403 so I might pan lube and try out a few as cast slugs. Wish me luck!

[Michael J. Spangler]

Bueller ??
Does this sound normal for a 40 Cal barrel?

[williamwaco]

My S&W 4014 measures .4008 - .4011.

[RobsTV]

Yes, my Shield slugged at .4025 to .403
But largest that will reliably chamber is .4015.

Seems like there is a tiny pad at the start of each rifling groove?

[Michael J. Spangler]

thanks guys!

robstv i assume you've shot cast in your shield then? how did it go?
my boolits drop from the mold at about .4026 ish. i was going to try to pan lube a handful and load them as cast to see how they shoot. sounds like i might have an issue with that.
what mold where you using for the .40? i have a 401638 that i've cast a handful with to try out.

[RobsTV]

Not going well. Leading of course. Still trying different things.
See above post for photos of groove pad mentioned.

Using Lee 401-175-TC.

Very accurate though.

With lead sized to .4025, had to smack the rear of slide hard a few times for each round to fully chamber. At least I found out the Shield is not possible to fire when a little out of battery.

[Michael J. Spangler]

That looks exactly like what my s&w 1911 barrel looked like.
I found that little step before the rifling was shaving off a tiny bit of lead, which was being ironed in my the next round.
Geargnasher and others said that it was a possible cause of leading. Once the chamber was reamed it went away.
Looks like that's how smith makes their barrels.

What kind of loads,lube and alloy have you tried to remedy the problem?

[RobsTV]

Alloy calculator shows the combination of stuff I use equals 2.22sn 4.32sb .08as 93.4pb=13.2, and Lee hardness tester shows 15.4 BHN after 30 days.

Trying various amounts of W231/HP38 and Carnauba Red. 4.7 to 5.3gr (stripped).
Also tried LLA and a combo of Carnauba Red and LLA (combo cured a 9mm).

---Next up heat treated a batch for testing this weekend.---
(I know, too small and too hard are two of the leading causes of leading, so with one stuck at too small, might as well try All In with that losing hand)

Do not wish to ream chamber in case of warranty work, and don't have the tool anyway. (Too bad there is no tool loan/share system here, like many motorcycle forums have). Might get another barrel when possible, and then see what can be done.

EDIT: Results from using harder 22BHN lead sized to .401 was the most accurate to date, and also the most leading (as expected), which shortened the amount of rounds usable until accuracy fell off dramatically. First 15-20 rounds were great (standing freehand, sub 1" grouping at 30 feet), next 10 were not so good with sub 2" groups, and by the time I hit 50 rounds was bad with 3" grouping. Need to feed larger boolits.

[uaskme]

Why dont you have your throat opened up. Take the pad off.

[RobsTV]

For me it looks like I will try to ream the throat open a little. Just spent about an hour searching this site for more info, and while I saw reference to using common things to make a reamer, nothing specific. Is there any thread explaining what is needed? Luckily have some access to a tool shop if needed.

Besides the Shield 40, also have Hi-Point 40 pistol and the 40 Carbine, and while the Hi-Point's eat everything with zero leading or issues, probably wouldn't hurt to tweak the throats on them as well.

EDIT: Just rented a 40 cal throating reamer from Elk Ridge Reamer Rentals for $15. Hope it goes well.

EDIT some more: And a few hours later they sent me tracking number that reamer has shipped.

Final EDIT: Throating reamer worked well. In the Hi-Point 40's, reamer cut like a hot knife through butter. The SS barrel in the S&W Shield was very hard and took several passes to make little progress and get it right. Would do this all again in a heartbeat.

[Michael J. Spangler]

So after switching to hi-tek coating I solved my leading issue completely.
Now I've been battling issues with feeding.
After months of picking up and putting it down it all dawned on me tonight.
The actual throat diameter is too small as you noted above. If I use a .403 bullet it rubs on the throat before the rifling even starts. That would be great for a bore ride section of a rifle bullet used in a bolt gun. Bad in an auto loader pistol.
So basically I had to seat the bullet with no bearing surface outside the case for it to chamber without sticking (barrel off the gun camber checking) of course that's way too short and caused issues feeding.
So I tried some plated a buddy gave me (same nose profile) .4007" diameter. They passed the plunk test in the barrel when seated to 1.1255" which was barely in the case and .100" too long to even get in the mag. I worked it back to 1.150" which would reliably feed from the mag and eject dummy rounds without catching the nose on the ejection port (not a big issue, I hope most of the cases come out empty at the range instead of all of this reloading fussing and checking with dummy rounds)
So I guess all that work I did to ream out my .401" die up to .403" doesn't help me at all.
I guess I should have checked the updates on this thread.
Well I'm going to load the plated .4007" diameter and as long as they don't tumble I'll be ordering a lee .401" sizing kit and sticking with the hi tek coating.
Seems like I solved the leading and I'll solve the feeding. Let's hope they don't tumble at .401"

I know this thread is old and robstv solved is issue a long time ago.
I just hoped my post update might help someone having a similar issue some day.

Sometimes the answer is right in front of you and you can't see it.

[RacingRedGT]

My .40 shield measured at .401

[oldfart1956]

Michael, glad to see you resurrect the post! Just picked up a Shield in .40 and currently running it through a cycling session. (500rds. min. for me) I'm almost certain not to be casting for this one, although I own 2 pistols in .40 S&W. Nice pistols, not unigue in any way but reliable and uncanny accurate with such a short barrel. Recoil is...robust. The grip angle does seem to point the gun downward a bit...odd thing. More used to the 1911's and Ruger single actions I guess. Please keep us Shield owners updated on your findings and loads. Many thanks. Audie...the Oldfart..

[Michael J. Spangler]

Hey Audie.
I've found the shield to be comfortable to shoot considering the snappiness of 40 and the compact lightweight gun itself.
I would definitely cast for it if you use hi-tek coating.

I just loaded some 135 plated TC to 1.160" over 5.5 WST. I'll shoot them Wednesday night. Seems like it's going to work just fine.
Now I need to order a .401 sizing kit from lee.