Neck turning for fire forming BRX

[AlNyhus]

I agree except.....dry cases and clean dry chamber for fire forming. Do not fire form with warm/ hot chamber. Case needs to grab the chamber for an even stretch. Yeah I know, but I disagree.

Other than a few factory chambers, I can't remember the last time I f-formed a case 'dry'. Benelli choke tube lube and Marvel Mystery Oil are my preference, though any sort of light sewing machine type lube will work..... 3-In-1, Kroil, a bit of Hoppes #9. Just something with a bit of lubricity w/o adding thickness.

My 30BRX's done using that process. The neck/shoulder 'blend' is smooth with ten 'Os' (smooooooooooth).

Lots of ways to skin cats, for sure. -Al

 

[JEFFPPC]

Other than a few factory chambers, I can't remember the last time I f-formed a case 'dry'. Benelli choke tube lube and Marvel Mystery Oil are my preference, though any sort of light sewing machine type lube will work..... 3-In-1, Kroil, a bit of Hoppes #9. Just something with a bit of lubricity w/o adding thickness.

My 30BRX's done using that process. The neck/shoulder 'blend' is smooth with ten 'Os' (smooooooooooth).

Lots of ways to skin cats, for sure. -Al

What bullet is in that BRX case and is it what you use normally?

 

[AlNyhus]

The bullets are my own 117's. I don’t currently shoot the BRX case but am going to revisit it in the near future. -Al

 

[Keefe300]

Other than a few factory chambers, I can't remember the last time I f-formed a case 'dry'. Benelli choke tube lube and Marvel Mystery Oil are my preference, though any sort of light sewing machine type lube will work..... 3-In-1, Kroil, a bit of Hoppes #9. Just something with a bit of lubricity w/o adding thickness.

My 30BRX's done using that process. The neck/shoulder 'blend' is smooth with ten 'Os' (smooooooooooth).

Lots of ways to skin cats, for sure. -Al

I tried your method and cleaned the chamber with a swab and non chlorinated brake clean every 5 rounds. I used 3 in 1 oil on a blue paper towel and rolled the cases across it like you would on the old lube pads. I then wiped the case with my fingers to make sure their was only a very light film of oil on the case. I then proceeded with fire forming.

So what I saw after fire forming and taking measurements is the head space measurement from a datum point on the shoulder to the base, has basically zero variance and was very consistent. This was measured with a Mitutoyo dial caliber and a .350 Whidden bump gauge.

Overall length had a variance of 0.0025 or two and a half thou difference

The web/.200 line/base had 0.00035 variance or three and a half ten thou

The shoulder to body junction had 0.00065 variance or six and a half ten thou.

I am proficient with a micrometer, but not an expert so these numbers are all very tight in my opinion and within the margin of error. So I would say this method produces some very consistent results. I also noticed that the shoulder to body junction seems to be sharper using this method as opposed to the dry and clean method.

I am responding to this thread because I have fire formed both ways now. The dry and clean chamber and the lightly lubed case method. I did this test to try something different. Often times we only do things one way and dismiss advice and or suggestions from other that may do it a different way. I like to take a different approach and try things for myself before I weigh in with any conclusions.

I hope this information is helpful or useful for you.

 

[AlNyhus]

Thanks for following up...glad to hear your results. To end up with good cases, I believe the first firing is everything.

Another thing that's beneficial even on 'normal' chambers is to push the shoulders back .015-.020 on virgin cases via a shortened shell holder. That, combined with a .020-.030 hard jam/seat, a light lubing of the cases, powders on the fast side for the chambering and a light stress relief of the neck/shoulder junction, helps achieve a perfectly f-formed case.