I am interested in trying a speed hammer. Seems the Moulds speed hammer is no longer available. Can’t even find spare used hammers to test. From what I have found, you can drill 1/4” holes using a carbide drill bit.

Anyone have some knowledge on actually doing this mod?
How many holes approximately? And any particular area to drill?
What is the minimum weight of hammer to maintain?

A few years ago I bought a package deal with 3 speed hammers and 1 factory because there was a kepplinger included. I used carbide endmills and copied some of the cuts without issue on the factory hammer. I think I still have a speed hammer or maybe the one I altered... I can try and dig it out if you need pics.

I did read that the weight should not go below a certain number for reliability but can’t recall the number. I think it was on the assra forum.

Thanks for the info. A picture would help. I am searching drill bits to use. I have a drill press but probably not stable enough for solid carbide bits as I know they are brittle. Seems carbide tipped bits are not recommended for hardened steel, but colbalt bits are.

My plan was to drill a few holes checking weight as I go. I am holding off for more info, as replacement hammers are non existent.

For answers to questions like this I would highly recommend going to the ASSRA site and sign on. There are a bunch of single shot gunsmiths who hang out there. While the main thrust is toward traditional vintage American single shot rifles, there's also quite a lot of "modern" stuff bandied about also.

Thanks. Just registered.

If you have any friends with a mill it would make life easier for you, however a carbide drill will work in your drill press - just clamp the hammer down. Anyways, hope this helps.... factory unaltered next to a speed hammer.

When I reworked the factory hammer, I didn’t cut off the “horn” because I like to use it as my cocking indicator as intended. It turned out fine, but I would likely do things a little differently if I tried another.




Something like this should be doable with limited tools on hand, and would lose a fair amount of weight.

Thanks. This is a huge help. I was not even thinking that the cocking indicator/horn could be removed. I will probably retain it depending on the amount of weight I can remove with only drilling holes.

Your build has inspired me to go through with the build I have been thinking about for a few years now. The MPI was my main concern as I didn’t want to end up with a pos.

As stated in that build thread, they do require a bit of work, but I am extremely happy with the end results. I had them cut the stock to length and fit a recoil pad. They added in a piece of micarta to attach the pad and they did a nice job of that.

I have it shooting under 1/2” groups and still fiddling with load development.

Just located another fiberglass stock set (B forearm) from a different manufacturer for a future build.

Had the local gunsmith mill out slots to loose some weight on these hammer. The before weights are seen at the top and after milling weights at the bottom. The rifle test fired fine, and left good indentations on the firing pin. I still have the factory springs, but may pick up a heavier spring to try.

I will get the rifle to the range this weekend to check accuracy.

Looks good, let us know how they work out.