Buffalo Bore 10mm in a S&W m&p ?

[WalterJones]

Walking thru Sportsmans in Albuquerque and they had a M&P in 10mm...so it came home with me

The manual that came with it isn't even updated for 10mm. So I called S&W to ask about Underwood and Buffalo Bore ammo. The lady didn't seem too knowledgeable and just kept saying they don't recommend it.

Now, I wouldn't make a day at the range shooting either because of expense. But I would like to carry it for CCW and/or a standoff with a bear.

What say you guys?

[jeremiah12]

I used my Google-Fu and this is the best I could find. S&W, on their website and in their manual, the one that comes with the M&P 10mm but is not updated for the 10mm states that any ammo that meets SAAMI specs is safe to use.

There are only specs for 10mm, not 10mm +P.

Most ammo manufacturers load 10 mm rounds on the light side, mostly to reduce felt recoil for target shooting. So gun manufacturers mostly tune their guns for these light loads.

I have owned a G29 for many years so I am most familiar with that. It is my backwoods/bear gun for when I go to Wyoming and Montana. I use hot Underwood ammo for it. I shoot a lot of the target ammo through it but I do put 500 rounds or more of hot Underwood rounds through it a year just to retain my skills.

Early on, I replaced the factory 17 lb recoil spring with a stainless steel 21 lb recoil spring and rod. That went a long way to tame the recoil and reduce stress on the frame. It also cycles the lighter loads just fine.

It has problems cycling .40 S&W so when I shoot that, I just switch back the factory recoil spring.

Buffalo Bore also discusses the issue of recoil springs and full power 10mm loads; https://www.buffalobore.com/index.ph...t_detail&p=114

I have personally visited the Underwood factory, my son lives close to them so I visit every time I visit my son and stock up. I asked Kevin at Underwood and he told me that all of their 10mm loads are within SAAMI specs so if the owners manual for your firearm says you can shoot ammo that meets SAAMI specs, then Underwood 10mm is GTG. Underwood's 10mm offerings are usually just a bit hotter than Buffalo Bore.

The M&P 10mm is newer and found little on it, but I did find two posts in the S&W forum relating to it. On person shot 200 rounds of 200 grain hard cast right out of the box through his with no problems and one suggest going with a heavier recoil spring because the hotter loads caused the slide to really batter the frame and he felt the 21 lb spring he replaced it with reduced the wear and tear and did not interfere with the cycling of the ammo. His brass still ejected about 2 feet away and he was in the snow and complained he could not retrieve his brass because it was lost in the snow.

So, that is the best I can find.

But now you have wanting to try one out. I cannot wait to retire and move out of CA. Of course, my son lives in IL and my birthday is approaching. I think I will probably stick with the G20 that I keep dropping hints about.

[Robotron2k84]

Ask Buffalo Bore. They spec the guns that will shoot their ammo. They are nice folks and will give you an answer.

sales@buffalobore.com

[L84CABO]

[WalterJones]

Looks just like an M&P 9mm...so close in dimensions it actually fits my M&P 9mm Blackhawk holster, just snug and sticks a bit when drawing

[WalterJones]

Jeremiah,

Thanks a bunch. My google-fu has been failing me on this issue.

If you have sources...how do I figure out how to obtain a stiffer spring? I'm having trouble tracking down springs specific to the 10mm model. I'm wondering if it would be the same spring dimensions as the .40

[jeremiah12]

Here is a link to a video of a guy testing his with a stiffer spring. He had failures with hot loads with the factory spring.

https://www.youtube.com/watch?v=ikRJUzZLrmE

He could not find one made specifically for it so he purchased one that could be modified to work and shortened the spring.

In the comments to his video, a person said he contacted Wolff Gunsprings and they confirmed that the 10mm version uses the same spring and rod assembly as the M&P 2.0 9mm/.40 cal version so that person purchased a 20 lb and 22 lob spring to test. He also suggested to polish the feed ramp to help reduce the FTF issues.

So, contact Wolff Springs.

[WalterJones]

Here is a link to a video of a guy testing his with a stiffer spring. He had failures with hot loads with the factory spring.

https://www.youtube.com/watch?v=ikRJUzZLrmE

He could not find one made specifically for it so he purchased one that could be modified to work and shortened the spring.

In the comments to his video, a person said he contacted Wolff Gunsprings and they confirmed that the 10mm version uses the same spring and rod assembly as the M&P 2.0 9mm/.40 cal version so that person purchased a 20 lb and 22 lob spring to test. He also suggested to polish the feed ramp to help reduce the FTF issues.

So, contact Wolff Springs.

Thanks again!!!

[9Cal_OC]

Looks just like an M&P 9mm...so close in dimensions it actually fits my M&P 9mm Blackhawk holster, just snug and sticks a bit when drawing