Bump on bolt

[JimCunn]

The .357 Mag has a 'bump' on the bottom of the bolt that drives the hammer back and down by about 1/8 inch, then lets it back up again as you operate the lever. I've not attempted yet to analyze the purpose of that function.

Anybody know offhand?

20220922_080802.jpg

[GFK]

Looks as though to assist with cocking the hammer.

[JimCunn]

Well, yeah - but is that it's only purpose?
Why does it release the hammer forward again after driving it back?

[GunnyGene]

Well, yeah - but is that it's only purpose?
Why does it release the hammer forward again after driving it back?

My .41 BBSC has that same little bump, I think to make sure the sear is fully engaged. It does not release the hammer back to the fired position when the bolt is in battery if that is what you meant. If it does, you have a serious problem.

[JimCunn]

That wasn't what I meant.
It releases it back to the position it was in immediately before the bump contacted it.
I agree about assuring the sear engages - I am curious about whether it also involves the transfer bar, but have not examined it to determine if that might be the case.

[GunnyGene]

That wasn't what I meant.
It releases it back to the position it was in immediately before the bump contacted it.
I agree about assuring the sear engages - I am curious about whether it also involves the transfer bar, but have not examined it to determine if that might be the case.

That's possible also. I never really gave it any thought, until you brought it up. Interesting question tho.

[JimCunn]

I thought so too.
Especially since it isn't ubiquitous on Henrys.
My curiosity is what is driving the question.
Since the bolt is not a snug fit in the receiver, it also slightly tilts the bolt when the bump is in contact.
But I doubt that that is significant.

[GunnyGene]

I thought so too.
Especially since it isn't ubiquitous on Henrys.
My curiosity is what is driving the question.
Since the bolt is not a snug fit in the receiver, it also slightly tilts the bolt when the bump is in contact.
But I doubt that that is significant.

My .41 is a pre-gate model (2018), so the bump has likely been standard for quite a while. Don't recall anyone else mentioning it. Doesn't interfere with function at all so I reckon it's all good.

[JimCunn]

"Doesn't interfere with function at all"

True, but it sure does grate and grind when it is in contact with the hammer.

[GunnyGene]

You could polish the rubbing surfaces. I did mine, and also use a tiny dot of Slip 2000 grease there occasionally.