Hey there. I looked up my question on google but didn’t find what the manufacturing processes for standard FSBs are. I have a BCM and was curious if the FSB is forged or MIM. I’m looking into purchasing a super gas block by geissele(love the “bombproof” pinning feature!) , but haven’t pulled the trigger yet due to it being MIM. Is this something I should be concerned about, or are normal gas blocks MIM?
My project will be on a standard M&P 10: I’m going to swap the gas block to whatever is the most sturdy low profile option and then free float it with either an MI rail or something else lightweight.
The Geissele gas blocks are investment castings, not MIM, as stated in the instructions that come with them (available on the Geissele website as a PDF).
Investment castings are fine as long as they are done right, and Geissele knows how to do them right. I believe most or all of their triggers are castings as well.
Standard FSB is a forging as noted. Once upon a time some commercial ones may have been castings (as claimed in Bushmaster ads from 10 years ago), but I doubt any are today given the widespread availability and low cost of basic components like that.
Thanks guys. Would reprofiling a standard FSB change the temper/forging properties of the metal? How much stronger/durable is forged steel vs investment cast?
Reprofiling a standard FSB may or may not change the metal properties depending how hot you get it (from grinding or sawing) but people do it all the time and it’s not likely to be any issue.
I can’t answer your second question readily, as it depends on the steel, manufacturing process in detail, and heat treatment. Basically if you but a quality brand you will get a quality part. Geissele is an excellent brand, if you’re still considering them.
I’m not aware of any version of the M&P10 that comes with a standard forged FSB. All I’ve seen have a low profile clamp-on gas block that is probably machined from bar stock. The block itself is fine but clamping is not the best attachment. I wouldn’t bother trying to reprofile one of those - if you want a smaller clamping block they are made by several companies including Daniel Defense and YHM. (YHM makes some mediocre parts, but their gas blocks are just fine.)
Thank you man. Do you think the super gas block would be my best low profile and robust option, or would a standard gas block with set screws/dimpled barrel/and rockset be equally strong? I’m a bit weary of the clamp on style myself.
Pinned is always going to be the strongest option. Your pinned options include the Geissele SGB and somewhat similar gas blocks from Black River Tactical and 87 Industries. I haven’t installed any of them yet (I have three SGB’s waiting for free time) so can’t offer comments of which one is better.
Set screw with dimples and Rocksett is a good option too. But for that matter you could simply apply Rocksett on the clamp screws of your existing gas block and have more security for very little money or hassle. When clamping blocks fail it’s because the screws came loose - when the screws are tight the clamped blocks are secure.
Any major changes are likely to void S&W warranty coverage. I suspect that you could get away with Rocksett on the existing screws without voiding the warranty though, especially if you removed the Rocksett before sending it in for some other repair.
In my opinion, from owning one, the M&P10 is a good rifle out of the box for its price, but if you are looking to invest money and make something special, you might be better off building from parts.
There are several reasons why a company would choose to forge a part over using other methods. Two of them are strength and throughput.
Sometimes a property of the part needs extra strength so a company will design the dies to flow the metal grains in a certain direction to be desireable for strength. And even then, it will only strength one feature or load direction. Therefore a forged part is not a blanket “stronger” than parts made via other methods.
I would bet that the vast majority of parts that are forged in the firearms industry are done so for throughput. For high volumes, it can be cheaper to forge parts. The tooling costs are extremely high, but if your production numbers are high enough, it may be worthwhile. I’m pretty sure this is the case for a FSB.