Gettin your bolt bushed in Canada

220 said:
Guess what happens if you have an over pressure ie: f- - - ed up reload, it will blow that bushing back in your bolt another spot pressure goes instead of where it is supposed to!
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If the bushing moves the machining was incorrect. When correctly done it will not matter what the pressures are, the bushing will just sit there within the bolt face. If it is not machined correctly it will most likely move the first time it is fired with a normal load...
 
Slimbo said:
It’s not to load over pressure, it’s to shoot a cartridge that uses small rifle primers in an action designed for large rifle primers.
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I was not aware of any difference between small rifle and large rifle firing pins... how do they design an action for primer size? I don't believe there is any difference with 700 actions.
 
the bushing Has a flange which supports it. I like to make the bushing long enough to guide the larger diameter portion of the pin. Reducing pin diameter will absolutely stop primer blanking at higher pressures.
Dennis, The cataract surgery is pretty amazing nowadays. I now have eyes like an eagle. An old, decrepit eagle, mind you, but an eagle nonetheless!
For those who may ask, I am also not taking any work.
 
guntech said:
I was not aware of any difference between small rifle and large rifle firing pins... how do they design an action for primer size? I don't believe there is any difference with 700 actions.
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Copy that lol. I must be confused

I found many many references to people bushing the bolt to reduce primer cratering and blanking when running standard bolt face cases with small rifle primers (6BR, 6.5x47, 6.5 creed SRP, 308 Palma brass)

If it’s not the small primers on a bolt face made for large primers, than what is it? They can’t all be running over pressure?
 
Slimbo,
To reference a Rem 700 bolt/firing pin tip diameter-
You have 4 bolt/breech face diameters-.378",.473",.532",.588"to fit any chambering from 17FBall to 338 Lapua.

Some 700 bolt/breech faces along w/ firing pin holes were/are oversized or countersunk to remove a burr during the machining process of said bolt head.

As you posted,some cartridge brass has the option for either a small primer or large primer depending on your brass selection.

Simple match-
OEM Rem firing pin tip diameter is .075"
Bushed breech face w/ turned firing pin tip is .062"

The .013" smaller diameter firing pin tip is to reduce the risk of blanking/piercing a primer cup upon firing.

The VENTURI effect is not taken into consideration by any that do the bushing/pin turning.

Layman's terms of Venturi Effect-

Pour water into a funnel-
Venturi effect
water exiting the funnel thru the venturi speeds/flows FASTER.
Physics can NOT be denied or eliminated.
 
Ok, so if I’m understanding what you’re saying my bolt may or may not need to be bushed to run SRP based on whether it was manufactured to proper tolerances in the first place? This is good news, it’s a nice old model 7 so hopefully it doesn’t need it.

Thanks for all the help guys I appreciate it.
 
Slimbo,
Eliminating assumptions-

1.Inspect the breech face of said bolt for any visual abnormalities.
2.Mic the firing pin tip diameter
3.Gauge pin the breech face firing pin hole
IF,the gauge pin dimension is .003"larger than the firing pin tip measurement & condition of the breech face is eroded or countersunk cut during the manufacturing process

You may want to bush the breech face
Or
ream the firing pin tip hole in the breech face & install an oversized firing pin

I have options that 99.999% of the 'smiths do not have.
A couple drops
work harden
cylindrical grind the firing pin tip
20 minutes of my time invested
10's of thousands of rounds fired w/o a breakage or bending issue.

We all have options!!
 
In all of the platforms & cartridges & barrel varieties that I shoot on a regular basis-

I have NOT found a cartridge from 22Hornet to 50 BMG or 380acp to 50WyEx in any platform or barrel that prefers maximum reloads.

Accuracy defeats Velocity 10 fold.

If 1 adheres to velocity over accuracy.......they can NOT drive said platform.PERIOD!
 
Slimbo said:
Ok, so if I’m understanding what you’re saying my bolt may or may not need to be bushed to run SRP based on whether it was manufactured to proper tolerances in the first place? This is good news, it’s a nice old model 7 so hopefully it doesn’t need it.

Thanks for all the help guys I appreciate it.
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I have a 6.5x47 on a standard M700 action. Bolt has not been bushed. I've never had an issue in close to 2000 rounds.
 
Guntec, it is obvious you did not read what I said, if it is properly done it does not matter under a wrongly loaded reload
It is a big fing explosion!
 
220 said:
Guntec, it is obvious you did not read what I said, if it is properly done it does not matter under a wrongly loaded reload
It is a big fing explosion!
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Well the thread is about bushing firing pins not trying to blow up rifles with bad loads... and if the bushing is done correctly it will not move within the bolt when you blow the rifle up with your bad load... and the original 700 extractor system will handle that very well with a very good chance of controlling the gases.

Now if one were to replace the 700 bolt with a PTG bolt (a bolt that does not use an original 700 style extractor) and fire a really bad reload the action will most likely blow up as that PTG bolt will not control the gases very well.

Unaltered 700 actions handle big explosions better than any other 2 lug action.
 
There are more features which contribute to primer blanking than pin diameter/tolerance. Spring rate, firing pin tip shape, firing pin protrusion, and the primer cup itself. Those bolts which feature the beveled hole in the face will always crater primers but may not blank if the bevel is not too deep. The difference with a reduced diameter tip and bushing is substantial. In one rifle which was blanking primers consistently, with loads which should not have done so. After bushing and reducing pin diameter it wasn't possible to crater or blank a primer even when loads were excessive.
In many cases, simply modifying the firing pin tip will do the trick and this is always my preference (always best to modify the cheap piece!) but in the case of the beveled hole in the bolt, they have to be bushed to correct the problem
 
Slimbo said:
Looking to run 6.5x47 in a model 7, so I guess I’ll likely need to Bush the bolt hole and turn down the pin for the small rifle primers. GRETAN in the states is not currently accepting work. Anyone know a smith that does this in Canada?
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Henry Rempel did a Winchester Model 70 for me, and preformed an outstanding job! Winchester manufactured the firing pin hole on a very large scale. Primers looked like a volcanic crater after firing; not anymore.
 
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