quote:

Originally posted by RogersGunWorks:
A client just brought in his latest acquisition, a brand new Ruger African rifle in 9.3x62. He had just come from the range where he found that Hornady ammo would not fire in the rifle but PPU ammo would fire every time. I checked with rifle's headspace with a "GO"gauge and found it to be perhaps .001" above minimum. Or nice & snug and within spec's. The PPU ammo that would fire would chamber with a .004" shim and the Hornady ammo would chamber with a .009" shim. The conclusion is that the Hornady cases are short in the headspace dimension to the point they will not fire. (Firing pin protrusion is .050".)

If there is a point(s) to all this it is that factory ammo is sometimes out of spec. and that headspace should be set with a gauge and not a cartridge case. Had this rifle been headspaced with the Hornady ammo, properly sized ammo from PPU and Lapua would not chamber.

Something that will cause problems is firing pin impact offset and primer sensitivity.

Firing pins should hit dead center on the primer, right on top of the tip of the anvil. However, if it is visibly offset, the energy to achieve ignition has to go up. At some distance from center, the primer will not go bang.

Different primers brands have different sensitivities, so offset problems will also have aggravating issues with primer sensitivity.

You did not show any pictures of the primers, so I don't know how hard the firing pin hit the primer. I will say, if the primer is too far away from the bolt face, you can still get a good looking primer dent without ignition.



I loaded up this LC79 and I reamed the pockets to depth. Actually, a little too deep. At a match, the M70 I was shooting would not ignite the little buggers. Even though there appeared to be a decent firing pin dent.

However, next match, I shot a M1a, which has lots and lots of firing pin energy and a lot of firing pin protrusion. All of the previously misfired 308 Win went bang in the M1a.

Primers are strange.

Guys.......F.Guddy is A moron that basically got run off accurate shooter forum be wise he's a goober.....

Tom.....man.....do not let him frustrate you! We already had one moron run Speer off, we don't want to lose you as well!

F.Guffy is A moron, plain and simple.

The guys just laughed him off of AS........

quote:

Originally posted by F. Guffey:
Ruger designed the rifle to use minimum length/full length sized ammo when measured from the shoulder/datum to the case head.

nope - just nope
1: you should start this with "my assumption is that" unless you have actual data as to how and why ruger designed anything
2: NO major maker of firearms uses minimum headspace on a mass produced firearm - these tolerances are IN THE SPEC
3: saami is VOLUNTARY - it is an industry guideline group, not CIP, which has the force of law to make regulations
- why did i take a tangent to discuss SAAMi? because there is NO legal standard, only a volunteer membership spec to ensure interchangeability.
4: headspace is the firearm's reference point, usually bolt or breach face to the datum of the chamber, NOT the case. simple example, persons that leverage the quirk that the 357 and 38 special have an overlapping headspace tolerance , but the "headspace" in that, in the case of 10mm/40sw, and various length shotgun shells that all can use the shorter length (2 3/4 in a 3.5" 12ga, for example) all disprove that case length has anything to do with headspace. and I expect we have all seen 300sav fired in 308 chambers.

here you go - you can verify all of my suppositions here
https://saami.org/technical-in...ge-chamber-drawings/

quote:

Originally posted by JTEX:
Guys.......F.Guddy is A moron that basically got run off accurate shooter forum be wise he's a goober.....

Tom.....man.....do not let him frustrate you! We already had one moron run Speer off, we don't want to lose you as well!

F.Guffy is A moron, plain and simple.

The guys just laughed him off of AS........

No need for that JTEX
We all have opinions
BB

quote:

4: headspace is the firearm's reference point, usually bolt or breach face to the datum of the chamber, NOT the case. simple example, persons that leverage the quirk that the 357 and 38 special have an overlapping headspace tolerance , but the "headspace" in that, in the case of 10mm/40sw, and various length shotgun shells that all can use the shorter length (2 3/4 in a 3.5" 12ga, for example) all disprove that case length has anything to do with headspace. and I expect we have all seen 300sav fired in 308 chambers.

F.Guffey has been playing the headspace tune for years, if not a decade if you care to research his activity on other forums.

After seeing enough posters fall over backwards, in hundreds of threads, posters doing such things as contacting SAAMI on the meaning of “cartridge headspace” and “chamber headspace”, I have come to the conclusion that F.Guffey is an attention seeking narcissist. F.Guffey has found a topic which puts him direct center stage, in the spot light, you are the audience, and this is the Guffey show. He has been manipulating posters for years.


All of the fuss and feathers F Guffey creates is of no value to anyone. He does not advance the state of knowledge, does not help anyone understand the mechanics, design, or dimensioning of firearms. He shoots no sacred cows, he helps no one. It is all attention seeking.

There are attention seekers pushing conspiracy theories, in all sorts of realms and topics, and what F Guffy promotes has direct parallels. It makes him the center of attention, his theme is unsolvable, unprovable, and vastly involved.

quote:

Originally posted by RogersGunWorks:
A client just brought in his latest acquisition, a brand new Ruger African rifle in 9.3x62. He had just come from the range where he found that Hornady ammo would not fire in the rifle but PPU ammo would fire every time. I checked with rifle's headspace with a "GO"gauge and found it to be perhaps .001" above minimum. Or nice & snug and within spec's. The PPU ammo that would fire would chamber with a .004" shim and the Hornady ammo would chamber with a .009" shim. The conclusion is that the Hornady cases are short in the headspace dimension to the point they will not fire. (Firing pin protrusion is .050".)

A reloader should be able to measure the length of the case from the datum to the case head; a reloader with the the basic skill of comparing case length from the shoulder/datum to the case head would have know the difference in length between the two rounds before attempting to chamber.

F. Guffey

Sounds like a broken record to me !

Hip

quote:

Originally posted by F. Guffey:
A reloader should be able to measure the length of the case from the datum to the case head; a reloader with the the basic skill of comparing case length from the shoulder/datum to the case head would have know the difference in length between the two rounds before attempting to chamber.

F. Guffey

and, again, a case, be it fired or virgin brass, is designed to fit into a chamber of a specific caliber (to simplify the conversation, we will set aside the rare cases of shared headspace)

as brass expands under pressure, filling the chamber, then springs back to a smaller dimension, one is NOT measuring the headspace of said firearm

one is measuring resultant SHAPE of the brass.

a gunsmith (which is the name of this forum) knows what headspace is, a reloader (i prefer handloader) knows how to ensure that brass fits the chamber -

the brass is NOT headpsace, and continued misuse of the term after being repeatedly informed is willful ignorance.

quote:

Originally posted by F. Guffey:

quote:

Originally posted by RogersGunWorks:
A client just brought in his latest acquisition, a brand new Ruger African rifle in 9.3x62. He had just come from the range where he found that Hornady ammo would not fire in the rifle but PPU ammo would fire every time. I checked with rifle's headspace with a "GO"gauge and found it to be perhaps .001" above minimum. Or nice & snug and within spec's. The PPU ammo that would fire would chamber with a .004" shim and the Hornady ammo would chamber with a .009" shim. The conclusion is that the Hornady cases are short in the headspace dimension to the point they will not fire. (Firing pin protrusion is .050".)

A reloader should be able to measure the length of the case from the datum to the case head; a reloader with the the basic skill of comparing case length from the shoulder/datum to the case head would have know the difference in length between the two rounds before attempting to chamber.

F. Guffey

I find it ludicrous to even think that the average reloader has the talent or the means by which to measure headspace from a fire-formed cartridge. Go back and let Jeffe's comment sink in.

quote:

I find it ludicrous to even think that the average reloader has the talent or the means by which to measure headspace from a fire-formed cartridge. Go back and let Jeffe's comment sink in.

I believe someone said 'I' couldn't. I picked up a rifle, chambered a round and then measured the length of the chamber without firing the rifle. the man that owned the rifle had 20+ head space gages that went all the way back to the day the datum was on the case body/shoulder juncture. He had gages that would allow the bolt to close and he had gages that would not allow the bolt to close. He had plenty of help; he was on a forum with world class resources all about rifles, ammo and gages.

In less than 5 minutes I informed him his chamber was .0025 longer than a go-gage length chamber; in 10 minutes I had measured the length of his chamber three different ways. And then I asked him if he had a 280 Remington case. I informed him I wanted to show him how to measure the length of the chamber from the outside.

He wanted to shorten the length of his chamber; I explained to him out of his 100 bolts there was not one of them that would shorten the length of the chamber .0025". I explained to him I had 30 new/old stock bolts and then I went on further to explain to him I did not have a bolt that would reduce the length of the chamber .0025".

F. Guffey

I really would like to know how you measure headspace to .001"; what do you use to measure it, it sounds like it may be masking tape on a heasspace gauge? What is it you use? And then do it in minutes.

quote:

Originally posted by F. Guffey:

quote:

I find it ludicrous to even think that the average reloader has the talent or the means by which to measure headspace from a fire-formed cartridge. Go back and let Jeffe's comment sink in.

...measured the length of the chamber without firing the rifle.

so, you didn't measure "headspace" with a fired round.. GOT IT

This discussion originally started with a statement that Hornady 9.3x62 cartridges were too short in the headspace dimension to fire reliably in a Ruger M77. I thought the problem was fixed by extending the firing pin protrusion from .050" to .063". In theory, that should have worked. It did not.

I fired the rifle yesterday and got 100% reliability with PPU factory ammo and an assortment of handloads. Yet, when I tried Hornady cartridges, only 3 of 5 would fire despite the increased firing pin protrusion. My thoughts then turned to the primers and I found that the primer cup was .003" below the head for Hornady cartridges and .005" below the head in PPU and Lapua brass--the ones that went bang every time. That led to speculation that the primers were dead, however cartridges that failed to fire in the Ruger fired in my FN M98 rifle. I would like to explain this but cannot. Instead, I have chosen to supply the client with handloads in Lapua cases that I know will go bang.

This discussion has included some very useful comments and some best left unread. Thanks to all.

Roger

quote:

so, you didn't measure "headspace" with a fired round.. GOT IT

I asked him if he had a 280 Remington round/case. I informed him I could measure the length of the chamber with a 280 Remington case or a field-reject length go-gage. I offered to modify one of his go-gages to a go-gage to infinity gage; he was not interested because the gage would no longer be ‘period correct’.

He contacted John Beard on CSP for help; John sent him a bucket of bolts. No one explained to me how someone in Irving, Texas ordered a bolt from across the country that would off set the length of a chamber .0025”; I would like to have had the opportunity to check the bolts John sent.

I also offered to form cases for the straight handle Rock Island period correct 1911 03, the man has the only hydraulically operated press I have ever seen.


“This discussion has included some very useful comments and some best left unread. Thanks to all.”

And for that reason I will never include my strange bolts in one of these discussions.

F. Guffey

ROGER - Tough one. Not much left to check. Aye?

Last resort idea. Can you measure the depth of the Ruger's un-fired primer dent from the face of the case and compare that reading to both the successfully fired Ruger round and the FN98 fired round?

quote:

Originally posted by RogersGunWorks:
This discussion originally started with a statement that Hornady 9.3x62 cartridges were too short in the headspace dimension to fire reliably in a Ruger M77. I thought the problem was fixed by extending the firing pin protrusion from .050" to .063". In theory, that should have worked. It did not.

I fired the rifle yesterday and got 100% reliability with PPU factory ammo and an assortment of handloads. Yet, when I tried Hornady cartridges, only 3 of 5 would fire despite the increased firing pin protrusion. My thoughts then turned to the primers and I found that the primer cup was .003" below the head for Hornady cartridges and .005" below the head in PPU and Lapua brass--the ones that went bang every time. That led to speculation that the primers were dead, however cartridges that failed to fire in the Ruger fired in my FN M98 rifle. I would like to explain this but cannot. Instead, I have chosen to supply the client with handloads in Lapua cases that I know will go bang.

This discussion has included some very useful comments and some best left unread. Thanks to all.

Roger

Did not the old gunsmith use electrical tape in one or two layers on the case head, as the tape was a true measure of thickness..I recall that practice by some well known gun smiths of their day??

quote:

Tough one. Not much left to check. Aye?

Last resort idea. Can you measure the depth of the Ruger's un-fired primer dent from the face of the case and compare that reading to both the successfully fired Ruger round and the FN98 fired round?

I would say no, I understand I am outnumbered by the yes men, I also understand I have a chance if they are required to giver a rational.

F. Guffey

quote:

I fired the rifle yesterday and got 100% reliability with PPU factory ammo and an assortment of handloads. Yet, when I tried Hornady cartridges, only 3 of 5 would fire despite the increased firing pin protrusion. My thoughts then turned to the primers and I found that the primer cup was .003" below the head for Hornady cartridges and .005" below the head in PPU and Lapua brass--the ones that went bang every time. That led to speculation that the primers were dead, however cartridges that failed to fire in the Ruger fired in my FN M98 rifle. I would like to explain this but cannot. Instead, I have chosen to supply the client with handloads in Lapua cases that I know will go bang.

I would have measured the length of the cases from the datum to the case head. And then I would have measured the length of the chamber from the datum to the bolt face.

I have not wasted a lot of time messing with firing pins, I have 3 98 rifles with 8MM06 chambers. My 8MM06 chambers are .127" longer from the datum to the bolt face that my 8MM57 chambers.

Old bart b claims the case shortens from the shoulder to the case head .005" when struck from the rear with the firing pin. And then he adds the part about the shoulder of the case hitting the shoulder of the chamber. If any of that was true my cases would have necks on the case when ejected.

F. Guffey

quote:

Originally posted by F. Guffey:

quote:

I fired the rifle yesterday and got 100% reliability with PPU factory ammo and an assortment of handloads. Yet, when I tried Hornady cartridges, only 3 of 5 would fire despite the increased firing pin protrusion. My thoughts then turned to the primers and I found that the primer cup was .003" below the head for Hornady cartridges and .005" below the head in PPU and Lapua brass--the ones that went bang every time. That led to speculation that the primers were dead, however cartridges that failed to fire in the Ruger fired in my FN M98 rifle. I would like to explain this but cannot. Instead, I have chosen to supply the client with handloads in Lapua cases that I know will go bang.

I would have measured the length of the cases from the datum to the case head. And then I would have measured the length of the chamber from the datum to the bolt face.

I have not wasted a lot of time messing with firing pins, I have 3 98 rifles with 8MM06 chambers. My 8MM06 chambers are .127" longer from the datum to the bolt face that my 8MM57 chambers.

Old bart b claims the case shortens from the shoulder to the case head .005" when struck from the rear with the firing pin. And then he adds the part about the shoulder of the case hitting the shoulder of the chamber. If any of that was true my cases would have necks on the case when ejected.

F. Guffey

I would still like to know how you determine the position of the datum, where it is, how do you measure headspace from there. It is an imaginary spot on the shoulder As set by the cartridge spec, how do you determine where it is? You need to use some sort of special measuring equipment, what type do you use?

Jim, forgive, I have found it easier to work off line with subjects that have a lot of details. For me it is a simple matter of drilling a perpendicular hole in to a block or through a plate. Many years ago an unknow reloader started the rumor that the datum was a line. He was very convincing, so convincing he drew am arrow pointing at 'the line' with the explanation
"datum line" and all reloaders were convinced.

I had trouble convincing reloaders on reloading forums the datum was not a line, I explained the datum was a circle/round hole. It was impossible to get a reloader to look at the case from the side, front and top.

There are 3 popular datum diameters, one is .375", next is .400 and I the third one is .420". The .375" diameter covers the 30/06 family of cases. the .400 covers the 308W family of cases and the .420" is used for belted cases.

SAAMI does not list head space for the case.

F. Guffey

Where is the datum? I said the datum was a round hole/circle; after drilling the round hole the datum becomes the top of the block the hole was drilled through. Makers of the datum want to male the datum case friendly so the give the edge of the hole a radius; and that turns their effort onto a comparator like the Hornady/Sinclair tool.

The complaint about the tool (that does not exist); drill one hole the datum diameter and the other the diameter of the neck. And then there are other improvements for measuring the length of the case from the datum (top of the block) to the case head.

F. Guffey

quote:

Originally posted by Atkinson:
Sambarman,
Not common but I have seen many new in the box guns fail to fire because of caked dryed grease in the bolt, and it slows the thrust or grabs and holds the bolt, clean the bolt is best, but just a bit of oil usually works...seldom if ever a severe problem and an easy fix in every case I have seen or had happen to me...My latest Ruger 220 Swift failed to fire out of the box, It was a NIB mod 77 in the box since 1973 or ?? I loaded it with WD-40 I had on hand and blew it out with a pressure hose and started shooting awesome groups and no misfires..cleaned it good later that day..

Yeah, Ray, that could be the problem. I must oil up this tablet to make it more reliable. That said, I did notice that the Ruger spring seemed a bit puny compared with the Mauser's and understand someone over your way does make stronger replacements - for some reason.

Dimensional tolerancing makes f Guffeys method of datum line measuring totally inaccurate on a brass cartridge. Datum line measurement will only work for a gauge that has a knife edge at the datum diameter, and angles away from that point that insure that the datum shoulder is the only point contacting the chamber. If the case isn't dimensioned perfectly to match the chamber angles and dimensions, some other portion of the shoulder or case may contact the chamber and determines the "headspace" fit of that cartridge. Add in dimensional tolerances of the chamber that result in less than perfect shoulder angles, and you have an impossible to measure situation. However, SAAMI anticipates exactly that, and gives a range of dimensions for both the cartridge and the chamber, so that they will play well together. Unless, of course, the tolerances stack up and they don't play well. Which is exactly where we started this conversation and was pointed out in the first posts in the thread.

A person can obscure the reality with red herring arguments that the datum is a circle instead of a line, circumvent the question of whether they use a fired or sized or whatever case to measure the chamber, etc, but the reality is that a person can comparatively measure the chamber and compare it to things they know to work, but actually getting a true "headspace" dimension using a non-precise manufactured item that is inserted into the chamber is ludicrous. Getting a true "headspace" dimension off of a case would require that the case be perfectly proportioned to spec, and that the chamber also be perfectly proportioned to spec. Any other dimensions and the contact point(s) the case headspaces off of would be something other than the datum line (circle to avoid the red herring answer). That point may or may not provide the proper case head to boltface clearance to operate properly.

With most pieces of brass, simply rotating the case by a few degrees in the chamber will produce a different measurement. A slightly out of round brass piece, or out of round chamber makes the line of Guffey's "datum circle" a wavy 3 dimensional shape instead of a flat, circular plane. In fact, both the chamber and the case datum circle will be two non-identical shapes that will not match each other at all. So, the real world "headspace" points will likely fall entirely off either the chamber or cartridge datum line, wherever the plus dimensions of the case and minus dimensions of the chamber happen to collide.

Wonderful response! Just the point I was trying to make.

f Guffeys

you still haven't explained how you can determine headspace of a firearm from fired brass -- without measuring the firearm.


"add such and so length from measured brass" .. is, well, SILLY - as you don't KNOW the age, condition, alloy of the brass, nor do you know the loading pressure of same.

You can devise precise loads from fired brass - sure enough -- an INFER other things.

but you can't measure headspace

quote:

Originally posted by jeffeosso:

You can devise precise loads from fired brass - sure enough -- an INFER other things.

but you can't measure headspace

That's the conclusion I came to some time ago. I decided I wasn't smart enough, and didn't have the right tools to ever measure "headspace". Headspace is a theoretical dimension that manufacturers use to make their products fall within a certain range of standard.

The reloader really doesn't care about headspace, what he cares about is the head to bolt face clearance of the particular cartridge he reloads. Fired cases are one tool that can be used to determine how to size and reload cases to best fit a particular rifle. You are essentially comparing a fired case to a reloaded one, to guess how well the reloaded one will fit the chamber/bolt space of the gun the fired case was formed in.

Using a fired cartridge from one chamber in another chamber is a pretty imprecise way to make a guess at the boltface to head clearance of another, presumably reloaded, cartridge. The cartridge should have been fired in the same chamber, and preferably repeatedly indexed to exactly the orientation as successive measurements are made, if any are made with the brass in the chamber.

Sambarman,
Ive owned a dozen or so Ruger 77s, old ones and the newer ones and never had a feeding problem or any other kind of problem. my only complaint was I never liked the shotgun safety on a rifle of any kind and they fixed that..but I never had a problem with the shotgun safety just didn't like it, and fixed that with a mod. 70 safety and a custom trigger pull by Tony BArnes on my old 30-06...

As to the headspace problems of this thread, I'll let the gunsmiths fight that one out. I,ll just fire form the case and reload it to the fireformed specs like Ive had to do on about every old guild Mauser Ive owned..