Bat actions 17-4 SS

[Ironworker]

Okay, so BAT actions machined out of 17-4 SS. Others, if not all, were machined out of 416R SS. What's the significance of that?

 

[Walt Krafft]

17-4 is a bitch to machine compared to 416. In its hardened state it is harder and tougher.

 

[Ironworker]

So is an action machined out of 416R inferior to 17-4?

 

[Walt Krafft]

No. Both work fine as steels for actions.

 

[Alex Wheeler]

17-4 is more similar to chromoly in terms of toughness. In my experience, all thing equal a 17-4 action will take higher pressures. Some of the loads we run in Bats just wont work in others. Now, heat treat plays a role too. So I am not saying all 17-4 actions hold more pressure than all 416 actions. But if you look at how small the lug surface area is on a Bat B or DS vs all other actions in that class AND they hold as much or more pressure than all others I think you would agree.

 

[rijndael]

What about the gall'ability of 17-4 vs 416? I assume it comes down to proper heat treat, but I'll let the others comment on the details.

 

[Ironworker]

17-4 is more similar to chromoly in terms of toughness. In my experience, all thing equal a 17-4 action will take higher pressures. Some of the loads we run in Bats just wont work in others. Now, heat treat plays a role too. So I am not saying all 17-4 actions hold more pressure than all 416 actions. But if you look at how small the lug surface area is on a Bat B or DS vs all other actions in that class AND they hold as much or more pressure than all others I think you would agr

 

[Alex Wheeler]

17-4 does seem to gall easier. But thats easily preventable

 

[Ironworker]

Could you help me here regarding holding more pressure? I load too hot of a load in my Terminus, and I blow a primer; won't the same thing happen in a Bat action? The cartridge case is the weakest link isn't it

 

[Alex Wheeler]

No. If your ignition is up to par you will lock the bolt up before you blow a primer. When I say holds more pressure I mean how hot you can load and the bolt still opens normally. For example, a model M has really big lugs. Normally they will give you no indication of high pressures. You wont know you wrecked the brass until you measure a case or try to seat a primer.

 

[Alex Wheeler]

Bat made some Bs with M sized lugs back in the day. I really want to get my hands on one of those.

 

[LVLAaron]

I'd like a short M please.

 

[Alex Wheeler]

MST is a short throw M. Its an M length bolt though not a B.

 

[gunsandgunsmithing]

Just my 2 cents but it's mostly about application and either are well beyond simply sufficient for actions. 416 is typically hardened to a suitable hardness level for it's application prior to machining, taking into account it's application and machinability when deciding how hard you take it.

17-4 PH is precipitation hardened and can be machined in its annealed state prior to hardening without significant warpage. It can be a bit harder than 416 but it all depends on the heat treat for both, respectively.

Carbide is hard but not very tough, so just an example to illustrate that it's not only about hardness but a compromise of hardness, toughness, machinability and stability. For our application here, either is very suitable at proper heat treats and it's mostly about how a given company chooses to incorporate either into the way they build actions, way before a cutter touches either of them.

 

[3Sigma]

Does anyone know what the typical final hardening temperature they use? H1100, H1150, or lower? The lower the final temp, the harder and more brittle the final product. I like H1100 or H1150, as it is much tougher and crack resistant while still being pretty hard for SST. I would be scared of an action finished at H950. With that setting, if you need more corrosion protection or strength go Titanium or Inconel.

 

[LVLAaron]

MST is a short throw M. Its an M length bolt though not a B.

I want an M that's built for a BR/Dasher. I'd call it the MSS - M Short n Stubby

 

[jackieschmidt]

Let’s get real here.

There is no contest between the tinsel strength, yield strength, impact strength, and ductility, of the Precipitation Hardenning Stainless Steels such as 17-4, 15-5, etc when compared to 416.

The reason action manufactures use 416 is that it is adequate for the task on hand and can be bought as pre hardened bar stock. The only thing it has over 17-4 is it’s relative free machining qualities. This allows lower tooling cost and higher production rates.

The advent of CAD/CAM Machining has allowed just about anybody that can program a machine to toss pre hardened bar stock into machining centers and turn out actions.

Bat not only uses 17-4, they also do their own in house heat treating. This is far superior to buying pre hardened commercial heat treated bars that could be manufactured any where on the planet and have a very wide tolerance in the actual RC harness.

I would venture a guess that Bat treats their 17-4 at around H1050, judging from the RC hardness.

I have actions machined from 17-4. Farley’s and Bats. Some years back, I bought a Stiller diamond Back drop port for my Rail Gun. It was a 416 action.

The loads I shoot in my Farley 6PPC with no problems would darn near lock that 416 action up. It didn’t take me long to can it.

Do you really need the extra strength and enhanced properties that actions machined from properly age hardened Precipitation Hardening stainless steels offer? Probably not. but it’s good to know you have the best.

 

[Jud96]

We use 416 for the steel actions at Pierce and I made myself an action for benchrest earlier last year. I’ve been able to load 31gr of 2023 lot N133 with a 68BT in a PPC without heavy bolt lift. I’ve actually prematurely loosened pockets in the Lapua 220 Russian before I got heavy bolt. We send our action body material out to be heat treated before they’re machined and then check the hardness when we get them back and they’re always within 1 point of desired on the RC scale. Our bolts are 4340 AQ and they’re also sent out as raw stock to be heat treated before any machining. I’ve never compared pressure limits of 17-4 to 416 in our actions. We did make a few actions from 17-4 but we had to change a lot of our programs to optimize it and it was more expensive and harder to work with. We went back to 416 and haven’t looked back. The lugs on my benchrest action have more surface area than a BAT DS or similar, so that could be why I’m able to run hot loads without issue. Maybe if our lugs were equal to BAT our 416 actions might pressure out sooner. I’m not entirely sure. Having said all of that, I don’t think either material matters unless you’re running MAX like many of us do in BR.

 

[gunsandgunsmithing]

Let’s get real here.

There is no contest between the tinsel strength, yield strength, impact strength, and ductility, of the Precipitation Hardenning Stainless Steels such as 17-4, 15-5, etc when compared to 416.

The reason action manufactures use 416 is that it is adequate for the task on hand and can be bought as pre hardened bar stock. The only thing it has over 17-4 is it’s relative free machining qualities. This allows lower tooling cost and higher production rates.

The advent of CAD/CAM Machining has allowed just about anybody that can program a machine to toss pre hardened bar stock into machining centers and turn out actions.

Bat not only uses 17-4, they also do their own in house heat treating. This is far superior to buying pre hardened commercial heat treated bars that could be manufactured any where on the planet and have a very wide tolerance in the actual RC harness.

I would venture a guess that Bat treats their 17-4 at around H1050, judging from the RC hardness.

I have actions machined from 17-4. Farley’s and Bats. Some years back, I bought a Stiller diamond Back drop port for my Rail Gun. It was a 416 action.

The loads I shoot in my Farley 6PPC with no problems would darn near lock that 416 action up. It didn’t take me long to can it.

Do you really need the extra strength and enhanced properties that actions machined from properly age hardened Precipitation Hardening stainless steels offer? Probably not. but it’s good to know you have the best.

Not arguing but at the typical action hardness, I don't see that ph steels have an advantage at all over 416. Now yes, if you wanna go harder, it can go harder than 416. Like I said above, for our application, I don't see a big edge going to either and both are MORE than adequate, IMO. As you know, production capabilities weigh into the best material as do your heat treating capabilities in house. As do machining pre heat vs post heat materials. Not saying you're wrong at all. In fact, just that under the conditions/state that we need our actions to be negates most if not all of the benefits of 17-4 while giving up some machinabilty on top of that. Yes, I think we agree that 17-4 CAN be taken to levels that 416 can not. Basically, both are more than enough and it depends on our heat treating abilities and how stable one vs the other is, if post machining heat treat is needed. I think a case could be made for either being superior under all of those parameters or circumstances. If you need hardness, 17-4 can certainly go beyond 416 though. That's without getting into surface treatments like nitriding. That adds a whole different element into the choices, IMHO.

Bigger cams and carbs are not always better either. Sometimes, they hold ya back. But that's just un American! Lol!

Same goes for threading... in most applications, tighter fit or sharper vee's is not better...it's just creating your own class of fit to which there may be no standard for and proper machining generally calls for a flat on top of most threads, too. Still, there are some that believe that means it's better, in some way. And, in some rare cases, it may be, but at a cost elsewhere, or at least raising the chance of "making the phone ring". Lol!

 

[Ironworker]

Let’s get real here.

There is no contest between the tinsel strength, yield strength, impact strength, and ductility, of the Precipitation Hardenning Stainless Steels such as 17-4, 15-5, etc when compared to 416.

The reason action manufactures use 416 is that it is adequate for the task on hand and can be bought as pre hardened bar stock. The only thing it has over 17-4 is it’s relative free machining qualities. This allows lower tooling cost and higher production rates.

The advent of CAD/CAM Machining has allowed just about anybody that can program a machine to toss pre hardened bar stock into machining centers and turn out actions.

Bat not only uses 17-4, they also do their own in house heat treating. This is far superior to buying pre hardened commercial heat treated bars that could be manufactured any where on the planet and have a very wide tolerance in the actual RC harness.

I would venture a guess that Bat treats their 17-4 at around H1050, judging from the RC hardness.

I have actions machined from 17-4. Farley’s and Bats. Some years back, I bought a Stiller diamond Back drop port for my Rail Gun. It was a 416 action.

The loads I shoot in my Farley 6PPC with no problems would darn near lock that 416 action up. It didn’t take me long to can it.

Do you really need the extra strength and enhanced properties that actions machined from properly age hardened Precipitation Hardening stainless steels offer? Probably not. but it’s good to know you have the best.

Now, that answered questions I never knew I had. Thank you