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Daryl_S
.577 member


Reged: 10/08/05
Posts: 17926
Loc: Beautiful British Columbia, Ca...
Re: Proof loads [Re: 9.3x57]
      #132548 - 17/04/09 12:07 AM

7%??? now 10% - Gads! Can you believe the stupidity? One would have thought such air-heads would have been removed from the gene pool eons ago.

Overloading with BP is virtually impossible to do in any case, unless the wrong grannulation is used - BUT with care, changing granulations can work in proof as can compression amounts - witness the .303's first loading, velocities and presssures generated - 70gr. of BP powder in a 45gr. case. But smokeless - 10% - Good Lord! They will create bombs - not get their 20% or whatever increase in pressure, but double pressure depending on the ctgs. Such are smokeless powders today. Oh well, glad this doesn't happen here.

Bordhunter50 - As to shortening cases to allow crimping bullets with cannelures in the wrong place - sometimes mandated by heavier than normal bullets, sometimes by merely having a bullet with a wrongly placed cannelure for a particualr repeating action - is normal handloading practise - in itself is not a bad thing - but not knowing what one is about with handloading IS a bad thing. .444 Marlins typically have 38" twists and will not stabilize bullets much heavier than 310gr. Those Marlins have a working pressure limit of about 44,000PSI and at that pressure limit, using the correct powder, can achieve 2,100+fps with that bullet, 2,200fps with a 300gr. To load at the limits in any ctg. one must know what one is doing.
Most don't. Witness the new English Proof Rules! 10% more powder --

BTW - Marlin themselves tested a M1895 .45/70 to 70,000psi, the bolt opened normally and the case fell from the chamber, indicating no excessive bolt thrust nor pressure exceeding the elasticity of the 'new' brass.

--------------------
Daryl


"a rifle without hammers, is like a Spaniel without ears" Edward VII


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KWK
.224 member


Reged: 28/02/04
Posts: 49
Loc: Illinois
Re: Proof loads [Re: Daryl_S]
      #163949 - 13/07/10 12:32 PM

Some here scoff at the idea of Birmingham using 10% more charge as a proof load. Certainly, this is not ideal; but with a quick look over Hodgdon and A-Square data, one finds a 10% charge increase can create a pressure increase of 20 to 50 percent, depending on the powder and cartridge. Proofs need 33 to 44 percent over pressure (SAAMI), so this is pretty good as far as rules of thumb go.

Similarly, using the data to compute K.E. rise compared to pressure rise indicates the German approach of requiring 25% more energy also seems to give suitable pressures, but on the high end of the proof range.


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Daryl_S
.577 member


Reged: 10/08/05
Posts: 17926
Loc: Beautiful British Columbia, Ca...
Re: Proof loads [Re: KWK]
      #163997 - 14/07/10 12:44 AM

I agree in theory, but - merely increasing a charge of X powder by 10% and calling that 'OK' is not the way to do it for the private handloader.

Pressure equipment in a Lab is needed and that 'proof' load must be worked up to using such equipment. Much depends on the exact powder being used as some become unstable as pressure climbs above a certain level. This can cause pressure 'spikes'. Case capacity and shape come into the situation as well. Pressure spikes are to be avoided, but can happen with a very small increases in powder charge, below 10%.

Many smokeless powders do not react in a linear fashion and rules of thumb can get you into a world of hurt.

--------------------
Daryl


"a rifle without hammers, is like a Spaniel without ears" Edward VII


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KWK
.224 member


Reged: 28/02/04
Posts: 49
Loc: Illinois
Re: Proof loads [Re: Daryl_S]
      #164002 - 14/07/10 01:26 AM

For the handloader, I'm more comfortable with a 10% powder increase than I am with passing proof by visual inspection. Precise headspace gauges to detect any significant yielding are, I feel, more important than getting the pressure spot on.

I would, though, insist on chronographing the loads to be sure the fps indicates a fair rise in pressure. Looking over published load data, it appears fps rise gives you a much better indication of pressure rise than does charge increase.

Without question, both approaches are flawed, and I can cite examples of both not working as expected. Still, I think either is better than no proof load at all.

Beyond that, the handloader must resort to using strain gauges. The T/C Encore makes an excellent platform for such work.

If you can find a lab with a piezo barrel, send them cartridges each with a bit more powder than the previous in the series and have them tested in sequence until a certain pressure is reached.


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CraigK
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Reged: 16/11/10
Posts: 8
Loc: Johannesburg, South Africa
Re: Proof loads [Re: KWK]
      #171824 - 21/11/10 06:18 PM

This is an extremely interesting thread!

I am a member of the South African Proof House’s Technical Committee , the Standards generating body for Gunsmiths and South African Firearms Manufactures Forum as I would rather be part of the solution than have some “idiot” make a decision for me.

We defiantly have two camps regarding proof testing: Those in favour and those who think it is an outdated and archaic practice (with most of the firearm importers and dealers being in this camp).

In South Africa according to the Standards Act we are required by law submit all nitro firearms for proof testing at the Firearms Proof House at the South African Bureau of Standards (S.A.B.S.) in Pretoria. We have our own proofing standards but they are essentially an overwrite of the C.I.P. Standards (we are not members of C.I.P. though we have applied on numerous occasions to become members).

As a small manufacturer and gunsmith I am in favour of proof testing as our production runs are small or one offs and we do not have the luxury of qualifying the design as one would in say a military production or a large civilian production run (say like Remington would). I believe that all firearms that are built (or have had structural repairs, rebarrels, etc) should be proof tested as part of your quality control, it helps identify problems like occlusions in barrels, poor headspace, etc and helps ensure that you put out a safe, quality product.

There are many dealers, gunsmiths and individuals here who do not agree with me being in favour of proof testing and would love to have me “hung drawn and quartered” for being in favour of it. I am of the opinion that the primary reason they do not like it is that it adds costs and is inconvenient to do.

When we started manufacturing our muzzleloaders we wanted to submit them for a VOLENTARY superior proof along with our nitro firearms to the S.A.B.S. it created a massive negative wave from a certain sector of our firearm society as if I (an alleged well known and respected gunmaker) thought it was a good idea to proof test our muzzleloaders (not a current legal requirement) the powers that be (read South African Police’s Firearm Registry) would possibly consider amending our Standards Act to include the proof testing of new and used muzzleloaders.

The S.A.B.S. proof testing procedure is basically as follows:

• Undertake a visual inspection, including chamber and bore dimensions.
• Fire two proof cartridges (30% above maximum commercial). If they do not have proof cartridges they will add 10% more of the same powder to a cartridge or use a bullet that weighs 10% more.
• Fire a commercial cartridge
• Undertake a visual inspection, including chamber and bore dimensions.

If the firearm is still within the required specification they will apply their proof mark if not it is rejected. If the firearm is damaged or destroyed during proof testing bad luck you lose and if you feel they erred take them to court (been there done that).

As they, the S.A.B.S. feel it is imposable (?) to blow up a muzzleloader along with said negativity they have to date refused to voluntarily proof test our muzzleloaders, despite our Standards Act allowing for it as they claim not to have the expertise so we do a factory proof on them which comprises of the following:

• Visual inspection
• Fire a maximum recommended load e.g. 500 gr FFg and a patched 4 oz ball in the 4 bore
• Fire a proof load; 500 br FFg and a DOUBLE 4 oz ball in the 4 bore
• Fire a maximum recommended load e.g. 500 gr FFg and a patched 4 oz ball in the 4 bore
• Visual inspection

If the gun or rifle is still within specification we complete it.

This will always be a controversial topic but manufactures and gunsmiths do need to test their product and services in order to keep you the shooting public safe and themselves safe from the lawyers mentioned so I for one will always be in favour of proof testing.

--------------------
Life is too short to shoot ugly guns


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beleg2
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Reged: 15/08/07
Posts: 591
Loc: Bahía Blanca - Argentina
Re: Proof loads [Re: CraigK]
      #172237 - 28/11/10 11:15 PM

Thanks Craig for the info!
It is very intersting.
Im not an expert nor a gunmaker I have only made a few muzzleloadiers and I proof some of them.
Many years ago I made a 12 bore smoothbore rifle to be shot with double charge as hunters in Ceylon according to Baker. To proof it I shot the provitional beligium or british proof (IIRC) that is double powder charge with 1.33 lead (I used 7# shot).
I also made a 12 bore howdah pistol and also proof it the same way.
Both guns were underhammers.
Thank you very much.
Martin


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DoubleRifle999
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Reged: 06/02/12
Posts: 24
Loc: North Carolina, USA
Re: Proof loads [Re: beleg2]
      #210222 - 06/06/12 09:45 AM

I thought I would bring this one back up again---seems like I have done that a couple of times recently!!

Since I am in the beginning stages of a build (and maybe two..!!), this subject holds more than a passing interest for me. I have read the entire thread----and something seems to be missing from the discussion.

I won't argue the advisibility of using shotgun actions or whether "proofing" is necessary. I think it is a great idea and so will proceed with that in mind. Here is what strikes me as odd: If you are considering a proof load and are wondering how to proceed, why not just develop a proof load?? Purchase a couple of boxes of new factory ammunition from different manufacturers. Take one or two rounds from each box and package them for shipment to a ballistics laboratory--these will be your "controls." Include with them some prospective proof loads of your own (maybe start with two rounds at "book max" then two at +4 percent, two at +6, two at +8, two at +10.....) or some similar arrangement. Have these rounds pressure tested by the lab. It will then be VERY easy to arrive at a proper "proof" load as required by the proof houses. No guessing, problem solved.

We know the parameters for proof (as published by the proof houses), we know what the manuals indicate as "max loads" and what that means (as evidenced by the manuals themselves), we know the design pressure parameters of the cartridges (as published by SAAMI or Birmingham or whoever..??), Soooo.....it seems a simple matter to load up a few rounds and have them pressure tested to determine a load that falls within the proof parameters of the proof houses. Yes..???

It goes without saying that you will need to record the load information of your test loads and mark them in a manner to identify them so the lab can record them properly on a data sheet. The only sticking point seems to be the availability of a ballistics laboratory. I know there are several (two or three..??) in the U.S. and all of the European proof houses can do this as well. I suspect there are labs "down under" as well and for that matter anywhere ammunition is developed and loaded.

Of course, I could be all wrong about this......

--------------------
...Howard...

Have tool will travel..

If you are not part of the solution,....You are part of the problem!


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Birdhunter50
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Reged: 03/06/07
Posts: 811
Loc: Iowa,U.S.A.
Re: Proof loads [Re: doublegunfan]
      #265717 - 30/05/15 10:38 PM

Doublegunfan,
According to some of these guys, self proofing your newly converted gun is impossible for an individual. I say that they don't have any experience with doing a proof test to begin with, in other words, they are prejudiced against any converted gun. You should carefully measure all the various parts and places they talk about in here, but in the end, it is the proof loads and the firing of them that will tell you if you have done a good job or not.
I have proofed many converted doubles, several of them on Beretta frames by the way, and here is how I do it. You need to figure out what is the heaviest bullet that is likely ever to be fired in your new gun. In other words the heaviest standard bullet for the caliber. Then you need to know what the load will be that you want to regulate it at, including the powder type and amount.
Taking the regulation load, you must make up a bullet, or buy one, that is 20 % heavier than the load you intend to use. It may be hard in some cases to come up with a bullet that is 20% heavier.
You don't need to worry about what the bullet is going to look like, it just has to fit the bore properly and be 20 over the regulation bullet weight. If necessary you can purchase a cheap aluminum bullet mold and re-cut it to make the bullet 20% overweight.
Next you need a proof testing fixture to hold the gun, I will try and enclose a picture of the one I use. Mine holds the gun upside down but that works out very well. I load both chambers and fire the first one with a long cord, then I move the cord over to the other trigger and fire it off.
I do two proof loads through each barrel, then two regulation loads, then I check out the gun. I have never had one fail yet, and some of them have been proofed for pretty heavy loads. Calibers proofed so far include a .600 special, 2 -.577's, 2 -.405 Winchesters, a .45-120-500, several 45-70's, several 20 gauge rifled slug guns, and 2 -12 gauge rifled slug guns.
None failed the proofing tests and all are still working and shooting at this time. I realize that 20% overload is more than many people use, but I feel that it is necessary to be sure the gun is sound. Good luck with your Beretta conversion. What do you think is the average working pressure of your load? You should be right about up towards the top end of what should be used in a conversion gun. I take it that your Beretta has no crossbolt in it, is that correct? The gun shown in the picture is actually clamped in sideways, it is a Ruger 20 gauge Red Label converted to a 45-70. Normal doubles are put into it upside down to test. I also mark the regulation load on the barrel flats so that everyone knows what it is proofed for. Bob



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Birdhunter50
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Reged: 03/06/07
Posts: 811
Loc: Iowa,U.S.A.
Re: Proof loads [Re: doublegunfan]
      #280569 - 08/04/16 10:55 PM

Doublegunfan,
How did the proof loading turn out on your Beretta 411? I am still interested in your project. I'm afraid we kind of hijacked your original thread with some of our own opinions. Did you proof the Beretta with 30% overloads for the 444? That is a great cartridge but I would be leery of shooting hot loads in it. What ever you end up using as a service load, you need to mark the barrel flats with the information. That may keep someone in the future from using something higher in pressure than what you proofed your gun for. Bob


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Wayne59
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Reged: 20/06/15
Posts: 882
Loc: Lagrange Ga. USA
Re: Proof loads [Re: Peterb]
      #280580 - 09/04/16 12:40 AM

I will probable make some people mad but I would be willing to wager that as many guns have blown up after they were proofed as guns that wern't proofed.

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