here's my .243 load

[milboltnut]

38.5 grains of IMR 4064
85 grain Sierra HPBT GK (jammed into rifling) enlarged primer pockets
Lapua brass
CCI 200

3 shots @ at 100 yards




Here's the rifle.... Built on a 09' Argentine action with a Douglas extra heavy bull barrel target crown, bedded at recoil lug, 3-9x32 Tasco scope

[versifier]

Newbys do not try this at home!!!!! This is a good way to kill a perfectly good rifle if you aren't careful. A crush fit of jacketed bullet into the lands can cause serious pressure spikes and added to a possible overcharge is a recipe for disaster. It shouldn't be too difficult to find another powder that wiill give you that level of accuracy at a safe pressure level.

That charge is over MAX in two manuals and at MAX in another. It is certainly over MAX for your rifle - the enlarged primer pockets proove it. I don't know if it is the charge level alone or that in addition you are seating against the lands or both together that is putting you overpressure for that rifle. That is one reason I discourage the posting of charge levels as there are some out there who would assume it is safe and simply try it without working the load up.

It's a nice group, but pushing the envelope like you are doing IMO just ruins expensive brass that should have lasted many firings. Once the primer pockets are loose, the brass is toast. You will sooner or later learn the hard way exactly why Paul Mauser put the heavy gas shield on the m98's bolt. The side hole in the m95 didn't do enough to route the escaping gas away from the shooter's face when a primer blows out. Do the primer pockets still loosen if you back off and seat a little off the lands? Have you had the locking lugs checked for cracks by a competent smith?

[milboltnut]

Delete post. Sorry thanks for the accountability. I believe the 09 is a very stout action and can handle alot more than people think. I read an artical about a test PO Ackley did with some military actions and they held up to some very high pressures... Maganum calibers barrels were installed, the barrels blew apart but the bolts and actions were still in tact. And Hatchers Notebook shows pressure tests way above what the receiver/bolt is rated at and held.

To answer your Question I decreased the OAL and the primers don't flatten, and the pockets don't enlarge.

I was reading an artical by Jack O'Connor about pressure.... from Speers #10 edition load manual.........

And he said it's probobly not dangerous pressure with only enlarged primer pockets... so i just figured I'd be good. But wasting good brass isn't good and pushing the envolpe from the 7.65 arg pressures at 56K and the .243 at 60K... although at max with no pressure signs would be the safe guard. I think I'll stay away.... Thanks again.

[versifier]

No reason to delete it. There are a lot of new loaders who can learn something very important from it, and a few old farts like me whom the reminder won't hurt either.

It's a perfect illustration of what you see when you are experimenting and how to know when to back off.

Jack made that statement in the days before we could actually measure chamber pressures as opposed to estimating them with the copper crusher method. Nowadays we know from real world measurements that when your primer pockets loosen up you have gone beyond safe. When you get to the hotter end of the charge table, you inspect every fired case. And you also pay attention to the ambient temperature because a hotter load that was safe when you worked it up at 60*F might well be overpressure at 90*F. Primers signs like flattening and cratering do not always show up (but when they do you pay attention). Sometimes you only realize you're in the RED ZONE when the bolt gets harder to open (of course by then you have loosened up your primer pockets and toasted the cases, but you can't learn that until later when you're decapping them).

I am not surprised that backing off from the lands dropped the pressure. That is how the big high pressure Weatherby magnum cartridges manage it. They all have really long throats and it is usually impossible to seat touching the lands. The long jump allows the pressure to peak and not spike.

What many do not realize is that the listed MAX in the manuals describes the MAX for their test firearm only. Actual MAX varies from rifle to rifle and what is a safe load in one may or may not be safe in another of the same model and chambering. I have rifles that show real pressure signs well below "book MAX" and others that show no signs at all 10% and more above what the manuals say. The point is that you have to be constantly aware and watch for all those little signs as you work your way up. You have found your rifle's actual MAX with that powder and bullet. As long as you're careful about your OAL (and the temperature) you should be OK. Brass won't last as long as it would with lighter loads, but sometimes that's OK if you're getting the performance you need.

I shoot some wildcats and I use a lot of surplus powders, many of them have little or no data to go with them, so I HAVE to be aware. Some rifles will shoot their best with hotter loads, others do better a few steps below, a few are tackdrivers with minimum loads. You never really know with a new or new-to-you rifle until you have gone through a complete workup with a few powders and a selection of different weight and brand bullets. And just to kick you when you're down some of them like one powder at low levels and another much hotter for best accuracy. Ballistics is a science, loading is an art.

Ackley's and Hatcher's experiments taught us a lot, but they did not address the issue of the cumulative effect of firing many really hot loads over time and what it does to the bolt and the bearing surfaces that take the brunt of the forces involved. The understanding of metalurgy and the behavior of various steels under stress was poorly understood a century ago, and the alloying was sometimes primitive and inconsistant from batch to batch. This was also true of brass as well as ordinance steel. The brass has always been the weakest link in the chain. Case failures due to brittle poorly annealed brass were much more common back then and it was not unusual to get a faceful of hot gasses. Check out the differences between the bolt of your Argie m95 and that of the m98. (I have this recurring image of Paul Mauser's huge bushy beard on fire. If it didn't happen to him, it sure did to others and he had to listen to them complain.) Major changes in design like that happen because there is a real need for them. With modern brass the m95 is a fine and versatile action whose only practical limit for most common cartridges is its short length. I have one that I built a custom .30BR sporter on and I like it a lot. I use m98 actions when I need their extra length. Interestingly Ackley found the Jap Arisaka action (a Mauser variant) to be one of the strongest. But he did not try some really light low pressure cast bullet loads in it that weren't quite hot enough to obturate the brass fully to the chamber. Like I said, one faceful of gas is enough to make you a believer in the m98 bolt design.

[milboltnut]

@Versifier..... this is why I usally stay away from these gunboards.

Jack made that statement in the days before we could actually measure chamber pressures as opposed to estimating them with the copper crusher method. Nowadays we know from real world measurements that when your primer pockets loosen up you have gone beyond safe

Sorry, IMHO, this statement makes absolutely no sense... whatsoever.

Nowadays we know from real world measurements that when your primer pockets loosen up you have gone beyond safe

Isn't that what O'Connor used for pressure signs.... in his artical?

I shoot some wildcats and I use a lot of surplus powders, many of them have little or no data to go with them,

Now this is what Newbies shouldn't try at home!!!

Ackley's and Hatcher's experiments taught us a lot, but they did not address the issue of the cumulative effect of firing many really hot loads over time and what it does to the bolt and the bearing surfaces that take the brunt of the forces involved.

His testing prooved that how much more these actions could take, so your statement is, well, empty.

The understanding of metalurgy and the behavior of various steels under stress was poorly understood a century ago, and the alloying was sometimes primitive and inconsistant from batch to batch.

Oh really? So how in the world did the T99 Arisaka, as primitive as it was, according to you, was one that took the most beating and survived? LOL

Case failures due to brittle poorly annealed brass were much more common back then and it was not unusual to get a faceful of hot gasses.

The artical mentioned proof pressure testing, so this would explain the brass failure.... and experimentation of loads in addition...

Check out the differences between the bolt of your Argie m95 and that of the m98

I have a 1909 Argentine.... which had/has a fine reputation of one of the strongest actions at one time.

With modern brass the m95 is a fine and versatile action whose only practical limit for most common cartridges is its short length

Nothing above the 7mm mauser pressures...

I have one that I built a custom .30BR sporter on and I like it a lot.

Looks to me that the .30BR is comparable to the 7.62x39...as far as pressure.

[milboltnut]

This is how your reply post should have looked like........

No reason to delete it. There are a lot of new loaders who can learn something very important from it, and a few old farts like me whom the reminder won't hurt either.

It's a perfect illustration of what you see when you are experimenting and how to know when to back off.

[milboltnut]

I can say that things aren't always as they appear.

I fired factory rounds that had flattened primers, so how detrimental is flattened primers?

[versifier]

Your 1909 Argie is most likely a model 95, distinguished in later versions by the hole drilled in the left side of the action into the bolt raceway for escaping gas from case failures and by the lack of gas shield as part of the bolt shroud. The design was very similar to the m92, and m93's, and many of all three variants were produced in 7x57 and 7.5, but the majority made for various S. American countries were m95's. They did not have the same safety/recocking system used in the m94 Swedes, nor the protruding stacked external mags of the m88's and m91's.

The Arisaka action is based on the m98, but the bolt is not, except for the claw extractor. The reciever ring is larger, thicker than the m98. The 7.7's were crudely machined compared to the earlier 6.5's (especially the wartime ones - mine was described as "having been gnawed from round stock by a demented beaver with carbide teeth"), but that clearly did not reflect the quality of the steel they were made of. The potential problem with them (and with all older rifles) was that there was no way to tell when they were made if there were any internal flaws, cracks, or inclusions in the steel invisible from the outside. That is why they relied so heavily upon proof testing, but that did not catch all the bad ones. Alloying and heat treating techniques were very primitive compared to what we know and can do today.

I do agree that things are not always as they appear.

As to primers, it depends. Modern pizeo (strain gage) measurements of chamber pressures/time do not always agree with the visual clues of fired primers. That is, sometimes they do appear as pressures get too high and sometimes not. Most will agree it is always smart to pay attention when they appear. Conventional wisdom says that when they progress from moderate flattening into total flattening or cratering one should back off to the minor level. (Normally five stages are noted: minor flattening, moderate flattening, total flattening, cratering, pierced.)

When primer signs are seen upon firing factory ammo (and it is fairly common to find them in range brass at my club, several dozen per week in the summer, but only one or two per month in the winter) again one should be aware. I have seen factory ammo (and handloads) that showed no signs in one rifle crater the primers and stick the bolt in another of the same chambering. One could simply dismiss it and say that primer signs can be irrelevant, but in the interests of safety I would not ignore them when they appear.

Would it be a valid assumption to assume that every cartridge in a box of factory ammo is identical? A chrono will tell you that is not always the case and breaking down a bunch of loaded rounds and weighing all components confirms there is much more variation from round to round than in my handloads.

Is it enough to make a load go from safe to dangerous? With the fear of big lawsuits looming for the ammo maker I tend to doubt it in general, but I believe it is possible on occasion.

I personally suspect that such rifles may possibly be showing the ammo is at or approaching that rifle's individual MAX when no other signs than slight to moderate flattening show. I also suspect that certain rifles can show those same signs when pressures are not getting too high, but without access to a ballistics lab I prefer to err (if err it is) on the side of safety and keep the loads mild for them. When I see minor flattening (or worse) on fired primers from my rifles, I always put it down in my loading notes as well as the ambient temperature to see if the same signs also appear in cooler weather. If they do, then I will note that too and usually try a different powder and try to work up to the same velocity to see if that will eliminate it. I have more than one rifle that seem to be most accurate with hotter loads, but with them I will use loads that only show no more than minimal signs in the hottest weather. Some powders are much more temperature sensitive than others, and a chrono helps to figure out which ones are most sensitive. If I see a notable rise in velocity on a hot day when signs appear on the primers that were not there when I worked up (or tested factory ammo) the load in cooler weather, then I place more trust in the primer signs.

Conversely, I know that a load I worked up on a really hot day will always be safe to shoot in cooler weather, but the chrono tells me if there is enough of a velocity drop that I have to make adjustments for longer ranges.

So I will ask a general question to all, what do you do when factory ammo shows more than moderate primer flattening? And what conclusions to you draw from it?

[milboltnut]

Your 1909 Argie is most likely a model 95, distinguished in later versions by the hole drilled in the left side of the action into the bolt raceway for escaping gas from case failures and by the lack of gas shield as part of the bolt shroud.

It is not a M95....it says 1909 on the receiver.... and there's no hole in the receiver for gas to escape...

So I will ask a general question to all, what do you do when factory ammo shows more than moderate primer flattening? And what conclusions to you draw from it?

That it's "probobly not dangerous" .....Jack O'Connor

[versifier]

The 1909 is a m95 with the addition of a hinged floorplate. The exterior action dimensions are the same, the bolt is the same design, and the other parts are mostly interchangable, at least the German-made ones are. Like the early m95's there is no relief hole. The recievers read: "MAUSER MODELO ARGINTINO 1909" on the ring and DEUTSCHE WAFFEN-UND MUNITIONSFABRIKEN BERLIN" on the side if made in Germany, and either "D.G.F.M. - (F.M.A.P.)" or "F.M.A.P MAUSER MOD 1909" on the ring and "DIRECCION GENERAL DE FABRICACIONES MILITARES" on the reciever side if made in Argentina.
Ref: Mauser Bolt Rifles by Ludwig Olson 3rd Ed.

I don't know as I would be overly trusting of anything made in S. America back then, but they do seem to have stood the test of time well regardless of my opinion. I have been building custom hunting rifles on various Mauser actions since the mid-1980's. All of them have their plusses and minuses, but I like them all from m92 on up to m98 and the Yugo's.

[milboltnut]

The 1909 is a m95 with the addition of a hinged floorplate

You better go back and do your research because the 09 has a stronger action tha the 95. Prior 98 has a weaker receiver.

I don't know as I would be overly trusting of anything made in S. America back then

it what made in Germany...DEUTSCHE WAFFEN-UND MUNITIONSFABRIKEN BERLIN

Anything else you would like to tell me that I already know?

[backcountry]

versifier - I "think" you might as well save your breath ....... I believe we had a hatch of know it alls recently and they all flocked to the forums ........ several I follow"ED" seem to be infested