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Chamber pressures

 
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  #15  
Old 01-20-2013, 08:12 PM
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Join Date: Sep 2010
Posts: 8
Re: Chamber pressures

Wally, I think you have the right idea on the rechamber.

I would never touch the bolt or receiver.

always work on the cheapest part to replace, if you can.

how many threads per inch are the receiver threads? Or MM if you have them?
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  #16  
Old 01-20-2013, 09:36 PM
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Join Date: Jul 2009
Location: Northern MN
Posts: 205
Re: Chamber pressures

Big Wally,
This has turned into a bit of a gunsmithing thread...All is good in your proposal to obtain your desired result...Except that facing off just enough off the shoulder to obtain exactly one turn may not be quite that easy....Depending on your thread pitch ( I am assuming about approx 1:16) that means that 1 degree of rotation would require a .00017 inch depth of cut...This would mean you would not have much room for error regarding the extractor slot...If you miss this in your final cut then the alternative might be to widen the extractor slot or make a deeper shoulder cut and grind a custom spacer with a surface grinder...Also you may have to deepen that extractor slot.

Facing off the breech end for your new rim space will give you that .060/.063 extra you are looking for.....The K hornet reamer should clean it up nice...Make sure you get the throat you ask for....

Back to our discussion on pressures and seating depth...The hornet family is a perfect example of pressure rising with increasing with deep seating because it is a low volume case to begin with....I have seen this happen in my .221 fireball while looking for optimum seating.....We all realize now your concern was what will pressures do when loaded at the lands and with deeper seating the answer is yes they will increase for both reasons...(at least till someone proves otherwise I am pretty sure Mikecr will agree)!

Also thank you for the compliment, my days of being a lad left me long ago....I have been hand loading for near 50 years now and I fit my first barrel 40 something years ago...I too joined this thread to learn from these "lads".....There is a lot of good talent on here and a ton of information.....

Good luck on your project,
Randy
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  #17  
Old 01-21-2013, 03:34 AM
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Join Date: Sep 2010
Posts: 8
Re: Chamber pressures

Quote:
Originally Posted by MNbogboy View Post
Back to our discussion on pressures and seating depth...The hornet family is a perfect example of pressure rising with increasing with deep seating because it is a low volume case to begin with....I have seen this happen in my .221 fireball while looking for optimum seating.....We all realize now your concern was what will pressures do when loaded at the lands and with deeper seating the answer is yes they will increase for both reasons...(at least till someone proves otherwise I am pretty sure Mikecr will agree)!

Randy
so Randy, your experience disagrees with Hornady's experience?

have you had pressure testing equipment comfirm this in the Fireball?
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  #18  
Old 01-21-2013, 07:12 AM
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Join Date: Nov 2012
Location: wrexham north wales UK
Posts: 18
Re: Chamber pressures

Quote:
Originally Posted by nanuk-O-da-Nort View Post
Wally, I think you have the right idea on the rechamber.

I would never touch the bolt or receiver.

always work on the cheapest part to replace, if you can.

how many threads per inch are the receiver threads? Or MM if you have them?
If i touch reciever or bolt it will alter the rim/head space i have set up with my 17A/H and thats a no.no.no.
At the moment the 22H stainless heavy barrel is redundant i cant see me using it again in its present form.
I dont have the 17A/H gun at this moment its on loan to my gamekepper friend and cant get in my unheated garage/workshop caus of the snow so cant get a proper measurement but when i get it back i will uncrew the barrel one compleat turn and insert feeler gauges to lineup my reciever slot and that will give me a measurment to slowly remove off the shoulder
I do have a good heavy lathe and the skill to fit the barrel myself to give me the correct rim space but never used s chamber ream so i will leave that to a smith if i can find one.
Wally
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  #19  
Old 01-21-2013, 11:40 AM
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Join Date: Jul 2009
Location: Northern MN
Posts: 205
Re: Chamber pressures

nanuk-O-da-Nort,
Absolutely not, what I was trying to say that my seating tests on the .221 paralleled exactly what hornady portrays in their manual...As far as Hornady took them that is...

Hornady only showed velocity and pressure decrease in their illustration...And they inferred a co-relation in the test between the two...
My seating depth tests went through the whole gammit from .005 in the lands to "on" the powder, where velocities started increasing slightly as you should expect them to do...

I know that velocities alone do not indicate pressures and I do not have any pressure testing equipment but I am not one to argue with the laws of chemistry and physics..

Obviously as I stated earlier Hornady did not even try to emphasize these minor insignificant changes on that end of the spectrum but only the more drastic pressure jumps when the bullet is seated at,near or into the lands....
Their demonstration showed the effects of moving the bullet away from the lands and pressure & velocity dropped significantly this will always be true...

Without perfect test conditions yesterday( -7 deg F) I tried this test in a 6.5-06 that I just put together and am starting load development on..Same charge of h4831 same bullet berger 140 vld .010 into the lands 2912 ave mv,
.010 off/2888, .030 off 2871, .045/2853, .065/2855, .085(just on the powder)/2869, .095/2871(slightly compressed...Not near perfect test and only three shot strings but a trend one would expect...
Sorry if I confused anybody.
Randy
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  #20  
Old 01-21-2013, 01:00 PM
Junior Member
 
Join Date: Nov 2012
Location: wrexham north wales UK
Posts: 18
Re: Chamber pressures

Hi Randy.
Sorry if i turned the site into a gunsmithing site but any gun shooting site is a part gunsmithing site members need to know about saftey and pressures ect the actial shooting of the gun is only a small part of the enjoyment of hunting I have had a good few tips and sugestions from this and other sites and i thank you all for that but as i see it life is learnig and to live i need to learn.
Have a NICE day and good hunting to you all.
Wally
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  #21  
Old 01-21-2013, 02:02 PM
Silver Member
 
Join Date: Jul 2009
Location: Northern MN
Posts: 205
Re: Chamber pressures

No problem Big Wally, this site also has a great gunsmithing section and there are some really great professionals that visit it...If you run into any problems or snags they most likely can help you out...Keep in mind the spacer option I mentioned above because if that last cut is a thousanth too deep that will equate to over 5 degrees rotation of the barrel....But a precision ground spacer will put you back in business (I know I did this once or twice back in the day)....
Good luck again,
randy
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