Pressure signs in a Winchester 94 30/30

[Potashminer]

I've been loading for at least 30 years, but all my background was for either bolt actions or Ruger No.1's.
So, not having loaded for a Winchester 94 before, what are the pressure signs to watch for as one works up from a starting load? At lever action pressures, do you get the primer changes like on a bolt action? Tight extraction would definitely be a deal breaker for me, regardless of what the actual pressure might be.

 

[bigedp51]

The 30-30 Winchester at 38,000 cup or 42,000 psi will always have the primer protruding from the rear of the case. Meaning the chamber pressure is not great enough to push the rear of the case against the bolt face and make the brass stretch. I have a 30-30 Winchester 94 Trapper model with a 16 inch barrel and as long as you don't go over todays conservative load data you will never have a problem. The only problem you will have is getting over the lower pressures during workup and having soot on your case necks and possible unburnt powder.

The late P.O. Ackley did a experiment with a 30-30 Winchester 94 and removed the locking bolt. He removed any oil or grease from the chamber and cartridge and then fired the 94 Winchester and nothing happened.

The 30-30 case gripped the chamber walls and the only thing that moved to the rear was the primer.

Bottom line when you make workup loads starting at the suggested starting load and and work up you will learn a great deal about your rifle and loads. Meaning "when" the chamber pressure is great enough to cause the case to stretch to meet the bolt face and the primer is flush with the base of the case. And also why minimum shoulder bump is important when setting up your dies and not letting your cases stretch excessively when fired.

NOTE, low pressure cartridges like the 30-30 will headspace on the primer. Meaning the rear of the case never touches the bolt face with a dry oil free chamber.

 

[Slamfire]

Similar to a 336 action in that it's a rear locking bolt. Excessive pressure signs - cratered primers, excessive case stretch and sticky extraction.

Interestingly, according to this source -

In case you are not convinced, I will cite an experiment by P. O. Ackley, the intrepid, mid-twentieth-century, wildcatter and experimenter. In investigating performance of rimmed cartridges Ackley once took the locking lug completely out of an old Model 94 leaving the breech block with no support at all. As he tells it: “The rifle was fired several times with the barrel tight. All cases appeared to be normal except for excessive primer protrusion.”

http://ataleoftwothirties.com/?page_id=643

 

[hunters home]

The 30-30 Winchester at 38,000 cup or 42,000 psi will always have the primer protruding from the rear of the case. Meaning the chamber pressure is not great enough to push the rear of the case against the bolt face and make the brass stretch.

The late P.O. Ackley did a experiment with a 30-30 Winchester 94 and removed the locking bolt. He removed any oil or grease from the chamber and cartridge and then fired the 94 Winchester and nothing happened.

The 30-30 case gripped the chamber walls and the only thing that moved to the rear was the primer.

Bottom line when you make workup loads starting at the suggested starting load and and work up you will learn a great deal about your rifle and loads. Meaning "when" the chamber pressure is great enough to cause the case to stretch to meet the bolt face and the primer is flush with the base of the case. And also why minimum shoulder bump is important when setting up your dies and not letting your cases stretch excessively when fired.

NOTE, low pressure cartridges like the 30-30 will headspace on the primer. Meaning the rear of the case never touches the bolt face with a dry oil free chamber.

Great stuff to know. Been doing this for over 35 yrs and you still learn something, espically when I have 2 win 94 30/30.
Thanks

 

[Slamfire]

Base diameter is 0.422", and SAAMI-specified pressure limit is 42,000 psi so bolt thrust is estimated as -

42,000*pi*0.25*0.422^2 = 5874 lbs ! Incredulous how the bolt wasn't propelled out of the action.

That's one helluva strong lever then to hold back the bolt thrust.

 

[bigedp51]

Great stuff to know. Been doing this for over 35 yrs and you still learn something, espically when I have 2 win 94 30/30.
Thanks

My problem with my short barreled Winchester 94 was not burning all the powder at even max book loads. I had unburnt IMR-3031 powder that was causing dented cases in the chamber.

I ended up using Contender pistol data and using a magnum primer and 748 powder to cure the unburnt powder.

Also even more important is P.O. Ackleys experiment and the key words "dry oil free chamber" any oil or grease in the chamber will double your bolt thrust. Meaning if any oil or grease had been in P.O. Ackleys 30-30 the rifle would have had catastrophic explosion and a destroyed rifle.

Rifles are designed to be fired with a dry chamber that reduces the dead load thrust on the bolt face and bolt lugs.

Below is from the 1929 "British Textbook of Small Arms" and the British used the base crusher system with the chamber pressure measured at the base of the case. And when a rifle was proof pressured tested two "oiled" proof test rounds were fired. And on the Enfield rifle if the headspace increased .003 or more the rifle failed proof testing.

Bottom line if anyone tell you its OK to oil your cases to fire form them, then ignore this bad advice, this person doesn't understand the word bolt thrust.

Below is from the H.P. White Test labs

 

[bigedp51]

Base diameter is 0.422", and SAAMI-specified pressure limit is 42,000 psi so bolt thrust is estimated as -

42,000*pi*0.25*0.422^2 = 5874 lbs ! Incredulous how the bolt wasn't propelled out of the action.

The math does not apply to P.O. Ackleys experiment because the rear of the case never touched the bolt face and only the primer moved to the rear.

Bottom line the math formula is not accurate and depends on the strength of the case in the base. Example a military 7.62x51 case is made of harder brass and is thicker and exerts far less bolt thrust than a thinner commercial case. So throw out that worthless formula because its even less than a ball park guess on the amount of true bolt thrust.

Its simple, the case acts like a shock absorber and reduces the amount of bolt thrust in a "DRY CHAMBER". And your math only applies to a oiled chamber and the case not gripping the chamber walls.

And at 43,000 psi a .243 case has not stretched to meet the bolt face and only the primer is touching the bolt face. Meaning bolt thrust deals with the amount of chamber pressure, brass strength and the dwell time the rear of the case is touching the bolt face. Meaning the math formula is worst case scenario and not what actually happens in the chamber.

Below a .243 case at 55,000 psi and "estimated" bolt thrust, and case friction in the chamber. Meaning the max bolt thrust is on the left side of the chart with "zero" friction or a oiled cartridge. And as you can see when the case grips the chamber walls the bolt thrust is cut in half.

 

[Slamfire]

Stiction force is present for sure. Asymmetrical loading between the bolt locking block and the lever where it fits into the bolt, and it's the lever which prevented the bolt from being propelled out of the action with the block removed.

Not recommended of course to fire the rifle without the locking block in place. Getting the bolt propelled at speed into the face would likely ruin a shooter's day.

 

[bigedp51]

Stiction force is present for sure. Asymmetrical loading between the bolt locking block and the lever where it fits into the bolt, and it's the lever which prevented the bolt from being propelled out of the action with the block removed.

Not recommended of course to fire the rifle without the locking block in place. Getting the bolt propelled at speed into the face would likely ruin a shooter's day.

I'm not sure what your trying to say, but I can tell you with my 30-30 Winchester the rear of the case never touches the bolt face at 38,000 cup or 42,000 psi or max load listed in the manuals.

Meaning the only part of the cartridge that touches the bolt face is the primer in P.O. Ackleys experiment, and the locking bolt was removed from the rifle and the lever had nothing to do with it.

This can be confirmed with any caliber or type cartridge and starting at the suggested start load and working up. At some point in the workup load the primer will no longer be protruding and be flush with the base of the case. Meaning at this point the chamber pressure is great enough to cause the brass to "stretch" and contact the bolt face.

So again the "dry" 30-30 case was fired and the rear of the case never touched the bolt face. And it "NEVER" registered with your math formula for the force exerted by the case on the bolt face.

Now using your math formula at 42,000 psi how much force is the primer applying to the bolt face.

Rifle Chamber Finish & Friction Effects
on Bolt Load and Case Head Thinning.
FEA Calculations done with LS-DYNA
http://www.varmintal.com/a243z.htm

"Increasing the Coefficient of Friction to 0.55 the brass case head never does contact the bolt face for the
35,000 peak chamber pressure load. This condition would have the primer protruding slightly."

 

[Hank44]

the case head never touched the bolt, the case has gripped and not stretched rearward, the levers lockup is irrelevant hence the primer protrusion.

 

[Hank44]

painful....

 

[bigedp51]

the case head never touched the bolt, the case has gripped and not stretched rearward, the levers lockup is irrelevant hence the primer protrusion.

Thank you Hank44, you must be almost as smart, good looking and modest as I am. The devil made me do it........honest.

 

[Slamfire]

What in the world has Winchester been thinking all these years? Why don't they reduce Model 94 production costs by making these without the locking block?

 

[Potashminer]

So, that has been interesting! I started this because I was not certain about what pressure signs were to be seen as pressure increased in a Winchester 94. Forgive me, but most of the previous comments have nothing to do specifically with lever actions - most of what is said above is about "chambers" which are not different whether lever or bolt action. I am certain Mr. Sharpe and Mr. Keith of that era also did some odd things and published some odd thoughts to "prove" their thoughts regarding pressure developed in a cartridge as it fired, but that is not what I asked about. To repeat my question, in so far as a lever action is concerned, is there special / unique / unusual signs of excess pressure that one might observe, compared to what one sees in bolt action rifles, as pressure increases.

 

[bigedp51]

What in the world has Winchester been thinking all these years? Why don't they reduce Model 94 production costs by making these without the locking block?

Slamfire, I was banned from the Marlin reloading forum because the "super moderator" was telling everyone to lube their cases. And when I posted all my information on bolt thrust and not lubing your ammo the moderator banned me and deleted all my postings.

Some people will say and do anything to not be wrong...............meaning the moderator was a "super A-Hole" and was spouting the same math formula you are.

The proof is in the British base crusher system and how it read actual bolt thrust.

Cartridge Pressure Standards
http://kwk.us/pressures.html

"In Britain, a third set of crusher standards were developed, using a "base" crusher. The crusher was a short, thick tube placed behind a piston at the base of the cartridge, and the firing pin passed through the center. The cartridge case was well oiled before firing, to minimize cling to the chamber walls (if not oiled, the indicated pressures were about 25% lower). To prevent case rupture on set back of the base, the crusher was first deformed in a press to a pressure a bit lower than that expected in firing. The units were generally stated in British long tons per square inch, or tsi. Pressures indicated by this method run 10 to 20% below those indicated by radial crushers. Kynamco in England still rates their production cartridges with this method."

The problem with this method was firearms had to be re-proofed in Briton when sold again. The problem was the repeated proof testing with oiled proof cartridges would cause lug setback and increased headspace. They are now only using "dry" proof cartridges to re-proof firearms. But to this day the British military still uses two oiled proof cartridges on their military rifles. This simulates the extremes of combat usage but again if the firearms headspace increases during this test over a given amount (.002 to .003) the rifle fails proof testing.

Bottom line lubing your cases is like playing football without a helmet and lubing your ammo is like your rifle getting a concussion every time it is fired.

 

[Slamfire]

It's a very interesting topic and I appreciate your enthusiasm. But we should get back on course in regard to the OP's question.

 

[bigedp51]

It's a very interesting topic and I appreciate your enthusiasm. But we should get back on course in regard to the OP's question.

I agree, I bought a new stainless Ruger Vaquero last night and its time to fondle it "again".

P.S. The OPs question was already answered, if his primers are not protruding from the base of the case he is loading too warm.

Always remember Google is your best friend.

primers backing out on 30-30 cases
https://www.google.com/search?source=hp&ei=FajyWZWxDcHWmwGg4rWACQ&q=primers+backing+out+on+30-30+cases&oq=primers+backing+out+on+30-30+cases&gs_l=psy-ab.12...1313.14349.0.16887.35.34.0.0.0.0.264.3785.10j23j1.34.0....0...1.1.64.psy-ab..1.32.3548.0..0j35i39k1j0i131k1j0i20i264k1j0i67k1j0i131i67k1j0i10k1j0i22i30k1j0i22i10i30k1j33i22i29i30k1j33i160k1.0.ix1z8dBrmk4

The amount of head clearance is governed by headspace and rim thickness and every 30-30 I have ever handled had backed out primers from its lower rated chamber pressure.