Eaa witness 10mm springs?

[Wick123]

Hi, I have a eaa witness standards steel 45acp.  If I get a 10mm conversion kit (slide) do I need to change any of the springs (recoil, hammer, firing pin) to shoot full power 10mm ammo? Thanks. 

[ATLDave]

CW is to up to a 16, 18, or 20lb recoil spring.  I use a 16lb spring in my 10mm Match.  

[johnbu]

i would increase the recoil spring, but I don't shoot 10mm, so that is "theoretical".  the other springs don't need to be changed, but the hammer spring can "fine tune" the recoil force curve.  However, in a DA/SA gun that can cause the DA pull to become extreme.  Most don't want that trade off !  (I don't). 

[Ronemus]

Full power 10 mm loads will send your brass about 30' away unless you use a much stronger recoil spring.  I use custom springs that are the strongest that will fit in the space available, and have bobbed the ejector; that sends my brass 8' away, so there's some hope of finding it.

[leemoe83]

I was shooting a friends 10 mm Witness with the stock recoil spring.  We were shooting 200 grain bullets at 1200 fps (according to the box).  The recoil spring felt to light for the load and the gun would fail to feed intermittently.  It was a lot of fun until the slide cracked just above the ejection port.  I suspect the gun is undersprung for real 10 mm loads.

[ATLDave]

6 hours ago, Ronemus said:

Full power 10 mm loads will send your brass about 30' away unless you use a much stronger recoil spring.  I use custom springs that are the strongest that will fit in the space available, and have bobbed the ejector; that sends my brass 8' away, so there's some hope of finding it.

 

Shortening the ejector is the answer to taming the ejection.  You can put a 20lb spring in there and ejection will still be vigorous... on anything stout enough to run the gun reliably.  Chasing ejection-reduction with the recoil spring is a good way to make a reliable gun unreliable when it comes to 10mm Tanfo's.  

[Yondering]

9 hours ago, ATLDave said:

 

Shortening the ejector is the answer to taming the ejection.  You can put a 20lb spring in there and ejection will still be vigorous... on anything stout enough to run the gun reliably.  Chasing ejection-reduction with the recoil spring is a good way to make a reliable gun unreliable when it comes to 10mm Tanfo's.  

 

Shortening the ejector does tune the ejection, but it masks the larger issue of excessive slide speed with hot 10mm loads. The post above yours about slide cracking is a valid concern with these guns. You are correct though that the recoil spring alone doesn't do enough to tune for full power 10mm.

 

I forget the exact numbers, but in the 10mm Witness pistols I had (standard full size steel frame, not Hunter, Match, or poly), I ended up with extra power recoil springs, extra power hammer spring, and Wolff +10% magazine springs. 

 

Adding a brake/comp helps a lot to tame slide speed as well if you can tolerate it; with an effective comp you could go back to the lighter springs like a lot of us are using for 40 and 9mm. (To be clear, I did not comp my 10mm Witness pistols, but have done so with good results on other 10mm pistols.)

 

When we talk about "full power 10mm" to me that means at least in the range of 200gr @ 1200 fps, and likely hotter. For the guys shooting factory 10mm ammo that is barely warmer than 40 S&W, I wouldn't recommend the extra power springs. 

 

Once you get slide speed under control with the hot loads, you probably won't need to tune the ejector, but the option is always there. 

Edited July 2, 2019 by Yondering

[Ronemus]

A recoil buffer is also very useful to avoid peening the slide/frame from impact - even with a stout spring the slide is hitting the frame hard.

[ATLDave]

14 hours ago, Yondering said:

I forget the exact numbers, but in the 10mm Witness pistols I had (standard full size steel frame, not Hunter, Match, or poly), I ended up with extra power recoil springs, extra power hammer spring, and Wolff +10% magazine springs. 

 

I have not found anything beyond a 16 or 18 lb recoil spring to be necessary for my book-max loads of AA#9, although I have no experience with the base model guns.  2 Matches and 1 Limited are the basis of my views/experience.  

 

There was a bad batch of slides on the standard/non-Elite series guns that got out more than a decade ago, and those had slide cracking issues.  I doubt anything done with springs would have saved them.  Since then, folks on the internet have stoked fears of cracked slides on any Tanfo Witness 10mm.  A Henning guide rod helps, too, although that's true regardless of caliber, and has more to do with how the base of the guide rod interacts with the frame than anything related to slide velocity.  .  

 

[MikeBurgess]

One other thing, the 10mm case itself seems to eject much further than other cases from My Tanfoglios even when loaded with the same powder and bullet at the same velocity as 40sw cases. 

[Dugiv]

I've had great success with compensators for taming the slide speed on these guns. With a compensator I run a 14lb recoil spring in the elite match and a 12lb with a compensator on a hunter. Both guns cycle 100% and brass ejection is no more than 10 feet. Without a compenator the full fat 10mm stuff seems like too much for these guns. As you get to a 20lb recoil spring cycling the slide by hand becomes an issue and so due feeding certain style bullets. I recommend staying away from the "supercharged" ammo in general (doubletap, buffalobore) in general but especially with these guns. It seems like these slides are relatively light for their size which translates into velocity. My buddy has a Glock 40MOS (the 6 inch 10mm) and the slide is substantially heavier.

[blfuller]

Wolff springs go all the way up to 22lb for the full size Tanfo pistols.

 

On 7/2/2019 at 2:49 AM, leemoe83 said:

I was shooting a friends 10 mm Witness with the stock recoil spring.  We were shooting 200 grain bullets at 1200 fps (according to the box).  The recoil spring felt to light for the load and the gun would fail to feed intermittently.  It was a lot of fun until the slide cracked just above the ejection port.  I suspect the gun is undersprung for real 10 mm loads.

The Witness pistols have a different slide profile, more rounded and had a tendency to crack.  Compare the Witness slide to the higher end Match pistol slides and they have more material in this area.