What would do this to breach bolt face?

The Rossi Model R92, a lightweight carbine for Cowboy Action, hunting, or plinking! Includes Rossi manufactured Interarms, Navy Arms, and Puma trade names.
Dutch Oven
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Re: What would do this to breach bolt face?

Post by Dutch Oven »

Archer, that's interesting. Does that mean excessive headspace is a possibility after all? Let me know if I'm beating a dead horse.
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Re: What would do this to breach bolt face?

Post by Dutch Oven »

Sorry, after rereading your post, looks like you were just adding on to effects and issues associated with excessive headspace. It's almost 3:00 AM where I'm at , so I'm even slower than usual.
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Re: What would do this to breach bolt face?

Post by Missionary »

Headspace is easy to check. Place a layer of masking tape on the head of a case and see if the bolt will close with slight pressure. One layer with "snug" bolt pressure is fine.
Keep adding layers until the bolt closes with light pressure on the lever. 2 layers is getting loose. 3+ layers you have an issue.
We have a rifle we place O rings on the 44 WCF brass due to excessive headspace so the brass does not separate. Resizing is neck only and 3F Goex loads.
Way down south in Arequipa, Peru till June 2020.
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Re: What would do this to breach bolt face?

Post by Archer »

Dutch Oven wrote:Sorry, after rereading your post, looks like you were just adding on to effects and issues associated with excessive headspace. It's almost 3:00 AM where I'm at , so I'm even slower than usual.
Yep, I was mostly just stating an additional/associated effect/issue that comes into play with excessive headspace.

As Missionary mentions you can check to see how your ammunition fits your rifle. Different ammo may vary a little.

As I previously mentioned, you can use some modeling clay (playdoh can work) to get an impression of what the gap is between your bolt face and the barrel surface that would stop a shell from going forward. Warning, it CAN be a bit messy to use this medium and you would want to make certain you got all the clay out of your gun. You simply put some clay in the area where the bolt face meets the barrel and close the bolt then you take out the clay and measure the thickness. You have to make sure you don't get the clay in an area where it would keep the bolt from closing as well and you would want to take multiple readings.
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Re: What would do this to breach bolt face?

Post by Dutch Oven »

Grateful for all the knowledge you guys have shared. I've got plenty of masking tape, but no clay/playdoh. For the 92, would there be much change in headspace from one bolt to another, or would it be more about barrels or locking lugs, etc?
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Re: What would do this to breach bolt face?

Post by Archer »

Tolerance stack is tolerance stack.

First off don't borrow trouble. Get your part, put it in the gun and see if it looks ok.
Do the tape test. Measure your rim thickness. Measure your tape buildup thickness.
Check the total: .060 Min vs. .070 Max. ( https://saami.org/wp-content/uploads/20 ... g-Copy.pdf Electronic page 155) If it is a couple tou out of tolerance you are probably still fine. IN FACT you can check your old bolt while you are waiting for the new one to come in. Remember most tape compresses a little. Your measurement may or may not be what the gun actually is closing on. You may get different results with and without the ejector in place.

Now about that tolerance stack up...
The bolts should be 'the same' but there will be some slight variation acceptable in the manufacturing.
Assuming a CNC manufacturing mill and assuming that it is set up correctly and run correctly
(proper material used, material jigged consistently, cutters measured for wear in between runs so the machine compensates for decreased length/diameter, worn out cutters resharpened/replaced in a timely fashion, temperature maintained within a certain range for the facility during production runs, machine calibration verified and maintained on schedule, the machine operator doesn't 'tweak' feeds and speeds outside acceptable parameters, finished product acceptance checks in place and maintained, any post machining operations like deburring, finishing and so forth don't change dimensions, etc..)

Now assume the same parameters for all the other machined parts that interface with those parts and may cause additional tolerance stack: (Locking lugs, Lug raceways in the receiver, exact fit of the barrel to the receiver.

Although there are a number of factors that come into play among the parts, IF the design is correctly blueprinted AND the manufacturing is done correctly then the parts should fit together without additional adjustment being required. It is also possible that the design can be done in such a way that minimal manual adjustment is part of the assembly process. There may be a feature of one or more parts that is designed for some fitting that is considered necessary and required to make everything come out right.

If there's a problem what next?
From the standpoint of the factory they may have a bad part or a bad batch of parts. They might swap them out, send them back, destroy them or modify them so they are in spec depending on the cost to do so and whether or not they can be made safe to work. They are going to want to fix the problem that is causing the problem though because merely fixing the part or assembly in question is more work.

If there's a problem with your gun it can be more involved and potentially more expensive.
That is why Missionary is putting O rings on his ammo rather than having someone disassemble the gun and put either a new barrel on it or modifying the barrel so it can be turned 360 degrees deeper in the receiver, having the chamber end shaved off, recutting the extractor groove, and feed ramp or other features, refitting the barrel bands, forend, etc..

Again don't borrow trouble. Wait and see.
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Re: What would do this to breach bolt face?

Post by Dutch Oven »

Archer, thanks for the words of wisdom. That's a lot to chew on. I'm not too confident in Braztech's quality control and tolerances. I received the bolt carrier from Rossi today. That's the good news. The bad news is that they sent me stainless steel and mine 92 is blued. I could live with that, but the machine work is pretty bad and the design is a little different. It's longer and uses a slightly different ejector to name a couple. There's a Big F and S by the safety instead of a red dot which makes me think it's from an older production. I'll be giving them a call next week.
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Re: What would do this to breach bolt face?

Post by Archer »

That's disappointing.

They should have asked about the finish/material AND/OR should have been able to tell from the serial number of the gun IF they asked for that.
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Re: What would do this to breach bolt face?

Post by Dutch Oven »

They asked for the serial number at the start of the phone call. I guess I better confirm next time. When you and Missionary mentioned o-rings, do you guys mean the rubber ones or are you talking about something else?
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Re: What would do this to breach bolt face?

Post by Archer »

I'm not certain exactly how he's using them as it is the first I've heard of the practice.
I sort of assumed he was using them in front of the rim to take up the excess space and force the brass back against the bolt face. By neck sizing the brass he's preventing it from being worked down to below min chamber spec and then being blown back out to the chamber size each firing.

.44 WCF (.44-40) is a bottle necked cartridge but headspaces off the rim. The 4 degree shoulder isn't exactly a reliable point to headspace off of.
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