Anyone looking to buy more S&B 10mm, check out Midway:

http://www.midwayusa.com/product/328319/sellier-and-bellot-ammunition-10mm-auto-180-grain-full-metal-jacket

33-36 cents per round before shipping/discounts. I added one 1000 round box to my cart, then applied:
789541365 as a coupon code for 20% off
Then add the cheapest free shipping item to lower overall shipping price:

http://www.midwayusa.com/product/129448/cold-steel-blowgun-quiver-for-625-caliber

... and voila! 28 cents per round delivered. That's cheaper than what it costs me to make 10mm ammo using new starline brass.

Nice work! Looks like my math was a bit off on the powder quantity that my buddy and I pulled but the rest of the stuff matches up nicely:

http://imgur.com/a/cdpGH

Chrono data similar as well:

http://10mm-firearms.com/factory-10mm-ammo/sellier-bellot-10mm-180gr-fmj/msg57699/#msg57699

Promo code 56SALUTE gets you 10% off and free shipping:
Offer expires 05/30/16, 11:59 p.m. (EST)
Offer not valid at Cabela's retail stores.
Additional items will require paid shipping and handling.
Offer good on Standard Express shipping & handling only and U.S. deliverable addresses only.
All oversized and additional fees still apply.
This offer has no cash value and is not transferable.
Offer cannot be used on prior purchases or in combination with any other promotion, rebate, or previous offer.
No change will be given.
In the event of a return or exchange, refund amount will be less any discount applied to original purchase.
Not available to Cabela's employees.
Cabela's reserves the right to exclude certain products from this promotion.

I took a chance on Grabagun last year:

http://grabagun.com/eaa-wit-10mm-15rd-4-5-stl-wf.html

Their photo showed scalloped with no rail, but the one I received is not scalloped and has a rail (pardon the fingerprints but the finish is great):

Neat, only 65 million dollars:

I grabbed screenshots:

Indeed, thanks for compiling this list and thanks for all of those who contributed their data.

The brass all looked fine, with no signs of cracks or damage (my Witness is pretty gentle on brass although it does try to send it into the next county). It looked like it was making a good chamber seal based on cleanliness and I didn't see the primer doing anything weird (reflow, protrusion, etc). I haven't tried reloading any of it yet.

BTW, Sportsmansguide has it in stock now at $15.99/box for non-members:

http://www.sportsmansguide.com/product/index/sellier-amp-bellot-10mm-180-grain-fmj-50-rounds?a=1930938

Coupon "BRADSHIP" for Free Shipping No Minimum

Had a chance to chrono some S&B 10mm today and got:

Witness 4.5": 1111,1104,1108,1107,1095 (average = 1105 fps)
Glock 20 w/Lone Wolf 4.6": 1102,1094,1094,1123,1112 (average = 1105 fps)

This is about the same velocities as Armscor (at least the stuff I bought last year) and considerably below Sig 180gr FMJ which chrono'd 1224 fps from the EAA today).

I agree with the other posters that muzzle blast could cause erroneous readings but OP, does your chrono support metric SI units and is it possible the mode got switched? 450 m/s is about 1475 fps which is very stout indeed. My wife once turned salmon fillets into cat food when she had her instant read thermometer set to *C instead of *F. You do NOT want salmon to get to 130*C!

FYI, Cabelas currently has bulk 200 round boxes for on sale for $95 with a free shipping code if you add a $5 box of .22LR or something.

http://www.cabelas.com/product//2247664.uts?productVariantId=4551060

Not sure if this is related but I found that in boxes purchased last fall, "Armscor " is FMJ while "Armscor USA" is TMJ (completely encapsulated bullet). Back to back out of my Witness 4.5" the FMJ averaged 1115 fps while the TMJ was a touch spicier at 1138 fps. Out of the same pistol, Sig 180gr clocked at 1220 fps, for comparison.

I just got some but haven't had a chance to test it yet:



They came from:

http://tssoutfitters.com/shop/sb-10a-10mm-180-fmj-50-20/

... but they seem to be out of stock now. My buddy and I went in on two boxes and it came to $14.94/box plus $7.95 shipping for two or a shipped price of under 38 cents each. Here's an album showing the pulled bullet, what the powder looks like, etc:

http://imgur.com/a/cdpGH

Some math needed but it looks like 263.74 - 179.34 - 76.32 = 8.08 gr of powder.