So on my RIA ultra fs 10mm the hammer broke in half after about 1000 rounds , I installed a flat bottom firing pin stop and a Wilson 22 lb recoil spring at around 4 - 500 round count. So I send it in ( with factory fps and recoil spring reinstalled ) and the factory smith changed a bunch of parts and installed a 22 lb hammer spring (factory stock is 25 lbs ) . Not sure I like that this was done, I installed the heavier recoil spring a flat bottom fps to keep the brass from flying 30 ft . So what effect will a lower hammer spring have ? I’ve been doing some searching on this but would like to know what your thoughts on this are ?

And please let’s not turn this into mim vs forged , after this happened I googled 1911 broken hammers and found forged one’s have broken also .

Shoot it - 3 pounds on the hammer spring shouldn't make a much of - if any - noticeable difference in how the pistol cycles.

More than likely - the drop is to protect the parts in that argument we shall not mention...you're most likely not the first return with this problem.

MIM.

Shoot the pistol and make your adjustments based on the ejection pattern just like you did the first time. There is enough variation in pistols and spring specs to make this a guessing game when trying to do in advance. I prefer the flat firing pin stop and the heaviest main spring I can get away with in combination with the lightest recoil spring I can get away with.

Yes that’s my plan to shoot it and see , I have other springs on order and if I do swap back in the 25 lb hammer spring and the hammer breaks again I’ll either send it down the road or ai might put in a forged hammer .

With the lighter hammer spring the hammer is not resisting force from the slide as much, taking away some of the stress. Maybe a better trigger pull with the lighter spring?

But wondering about the flat bottom FPS. Did it, alone, change the energetic ejection distance? If not, I wouldn't want it. A square edge striking against the hammer. The first thing it would likely do is score a line on the hammer face, a stress riser.

Colvin,
You could maybe talk it over with the RIA gunsmith. Contact [email protected], the head customer service guy who may be able to arrange for you to have that discussion.

K]With the lighter hammer spring the hammer is not resisting force from the slide as much, taking away some of the stress. Maybe a better trigger pull with the lighter spring?

But wondering about the flat bottom FPS. Did it, alone, change the energetic ejection distance? If not, I wouldn't want it. A square edge striking against the hammer. The first thing it would likely do is score a line on the hammer face, a stress riser.

It did help a bunch , I’m new to 1911’s but from the research I did its quite common to install a flat bottom fps to slow the slide down. It’s not truly flat is does have a radius on the leading edge. So I’m not going to lie it had crossed my mind if the fps is what caused the hammer to break.

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This makes the most sense. The people at RIA tend to be very good.

The Flat FPS engages the hammer at a lower spot creating more pressure on the hammer and pin. Maybe an MIM hammer could be a bad mix with a flat FPS.

A 1911 was intended to be chambered in 45 ACP. not 10mm...................not much good can really come from that, but that's another conversation.

If you install a flat bottomed FPS, you should always put a small radius on the bottom edge that rides into the hammer................leaving it dead sharp is not a good idea at all.

You didn't want the MIM discussion but it's pertinent................MIM is simply not as strong as machined from stock or forged, period.

As for the reduced mainspring, that may drop trigger pull, maybe not...................in a 10mm, I'd surley go with the 25lb spring, even with the flat bottom FPS.

Here's a broken MIM safety of a S&W................& the safety is not exactly a highly stressed part.

JMHO, JMMV

MM

My guess is the FPS radius has more effect on slide velocity than the drop in hammer spring poundage. As mentioned, you want a small radius on the FPS, so evenly break the edge of your square bottom. The lower poundage was likely to reduce the hammers impact velocity on the slide (just a guess). If it reliably ignites all the primers, I wouldn’t worry about it.

If the hammer/MIM thing worries you, buy a new hammer and sear from somewhere like Wilson or C&S. Be aware that even Wilson uses MIM in their value line of hammers. They must be pretty sue than MIM in a hammer isn’t an issue if they put their name on it. If you are wanting to avoid MIM you need to read the description carefully.

Just to be clear , there is a radius on the flat bottom spring stop .

Yup, Any flaw in the hammer, MIM or not, is going to take a harder hit from a flat bottom firing pin stop plate. If I was going to carry that pistol I'd put a Brown barstock hammer in it.

Yessir.

The 3 guys I know that used RIA swapped the hammer, sear and disconnector right off the bat. With MM’s pic, I’d swap the thumb safety as well.

Wilson bulletproof products are not MIM, the rest could be.

'Flat bottom' is a relative term. It's flat bottom compared to the standard stop, but there's still a lot of radius. The FPS was flat bottom as designed by John Browning until 1918. It was changed to make the pistol easier to cock either using the slide or by hand. It's a change I make to most 1911's I plan to fire a lot and usually allows me to use a lighter recoil spring.

So I assume that’s a photo of a bar stock hammer in your RIA , if so did you install yourself and was there a lot of fitting involved ?

Usually, but not always, it’s drop-in. When it’s not, it’s often a binding thumb safety issue, which I’ve cured by “wearing in.” The only such trouble I’ve had has been with blued versions. The stainless versions always dropped in slick as could be:



My RIA 10mm still has its stock hammer, which does just fine:



Admittedly, I don’t yet have 1000 rounds through that 10mm.

Have you contacted [email protected], yet?

No I have not , just bought a Wilson bullet proof , hammer , sear and disconnect to install . For $100 I figured it’s a piece of mind not having to worry about it happening again .

Thanks JOG, this info & the OP clarifying that the FPS did indeed have radius in the leading edge changes the thought on that part.

I usually set up my 1911's like this.

The BE guns that only get low power target loads are sprung even lighter.

Short guns seem to do much better with less radius on the FP stop.