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Discussion Starter #1
I am having a difficult time finding a definitive answer on how to know when you are getting to maximum allowable pressure in a lever rifle. From what I understand, you will be long past overpressure for the action well before you see primer flattening or other usual pressure signs.

I am curious specically in cases, like mine, where you are dealing with a cartridge with little if any published load data. I have an early '70s Win 94 that was rebored to 35-30/30. The only load data that is out there is very anemic cast bullet stuff so I am out in uncharted territory regarding jacketed hunting bullets.

Many people have told me to simply use 35 Remington data backed off a bit, which is what I have done, but defining the top end has been somewhat of a gray area. I have worked up to near max 35 Rem loads and have had no extraction issues or signs of pressure on the cases but just want some assurance that I am not near or already overpressure for the action.

What do you lever gun shooters do? Specifically when dealing with wildcats.
 

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When the primers flatten , unloading a fired case becomes sticky, or the lever popping open during firing you know know your way beyond safe.
If you have a Chroni , you can see where the pressure spike is going to be .
 

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Discussion Starter #3
you know know your way beyond safe.
That's the problem. I don't want to get to BEYOND safe. I do have a chrony, but I was assuming that when a pressure spike was evident by velocities that I was again already past safe levels for the lever action. Meaning I didn't think velocity spikes would occur until you were at CASE maximum pressures, i.e. 60k psi or thereabouts, which is way beyond where I want to be with the rifle.
 

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Evan, you are correct in both senses: it's very difficult to judge a wildcat in a fairly weak action, AND you don't want to push it until you are well past safe.

Unfortunately, unless you have pressure-measuring gear (which IS available), the best you can do is a "waguesstimate" based on velocity. I'd set a speed threshold just about at what the parent cartridge develops and use the extra bullet weight to deliver the performance boost you seek. The 30-30 tops out at about 2200 to 2300 fps with its two most common bullet weights, and that's where I'd start getting very cautious with your bigger bullets. You didn't say, but I'd begin with 180-grainers and see what develops before I moved to 200-gr bullets. I'd probably also lower my velocity limit to 2100 for the larger ones.

God luck and report back on this interesting experiment, willya?
 

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Discussion Starter #5
Evan, you are correct in both senses: it's very difficult to judge a wildcat in a fairly weak action, AND you don't want to push it until you are well past safe.

Unfortunately, unless you have pressure-measuring gear (which IS available), the best you can do is a "waguesstimate" based on velocity. I'd set a speed threshold just about at what the parent cartridge develops and use the extra bullet weight to deliver the performance boost you seek. The 30-30 tops out at about 2200 to 2300 fps with its two most common bullet weights, and that's where I'd start getting very cautious with your bigger bullets. You didn't say, but I'd begin with 180-grainers and see what develops before I moved to 200-gr bullets. I'd probably also lower my velocity limit to 2100 for the larger ones.

God luck and report back on this interesting experiment, willya?
Thanks Rocky. I was hoping you'd chime in.

What you descirbed is essentially what I have done so far. Though I did start with the 200 gr. Core Lokt as that's really the only jacketed bullet I am planning on using for now. I wanted to get that bullet going at least 2000 fps and GUESSED that would be a safe target. I was able to do it with H-4198. H-4895 and IMR 3031 weren't getting me there.

I'm not a speed freak by any means, but if I could safely get another 1-200 fps I would just to extend my usable range a little.

Thanks again for the reply.
 

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This may help. Three general rules govern the end result of cartridge performance:

One: If case capacity and bore size are constant, the potential velocity varies inversely at one half the percentage change of bullet weight.

Two: If case capacity and bullet weight are constant, the potential velocity varies at one fourth the percentage change of the bore area.

Three: If bore size and bullet weight are constant, the potential velocity varies at one fourth the percentage change of the case capacity.

Importantly, those three rules are based on the assumption that peak pressure remains a constant. Since that’s what we’re trying to do here, let’s use the first two of those rules to see where we are.
Starting with the bore size change (Rule Two), going from a .300” to a .350” bore diameter (not groove) gives us about a 36% increase in bullet base area (.283 in² to .385 in²). That means we might expect about a 9% increase in velocity if all else remains the same. If a .30-30 conservatively gets 2200 fps with a 170-gr bullet, a .35-30 would get right at 2400 fps with a bullet of that weight.

However, here isn’t a .358” bullet of that weight, so we move to Rule One. A 180-gr bullet is about 6% heavier than a 170, so our wildcat .35-30 should get about 3% less, or 2330 fps. A 200-gr is 18% heavier than a 170, and ought to drop 9% of speed, getting 2000 fps.

So there you are. (And my initial “waguesstimate” wasn’t that far off!) Work up your wildcat until you hit 2300 fps with a 180-gr bullet, or 2000 fps with a 200-grainer, and you’ll be at about the same pressure as a normal .30-30 load. Which is certainly safe in your gun. In short, you did very well!
 

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I think you'd do better comparing the bullet's bearing suface in comparing the same weight bullet. With the bullet weight being the same for both (30 vs 35 cal.) the bearing surface of the 35 cal bullet will be less, therefore the drag imparted will be less and the pressure generated will be as well. Also would be wise to compare case capacity of the 30-30 and 35 rem in making judgements on powder charge changes. Be that as it may, I'd stick with published data for the 35 rem for what you're doing and go no farther in powder increases.
 

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Discussion Starter #8
This may help. Three general rules govern the end result of cartridge performance:

One: If case capacity and bore size are constant, the potential velocity varies inversely at one half the percentage change of bullet weight.

Two: If case capacity and bullet weight are constant, the potential velocity varies at one fourth the percentage change of the bore area.

Three: If bore size and bullet weight are constant, the potential velocity varies at one fourth the percentage change of the case capacity.

Importantly, those three rules are based on the assumption that peak pressure remains a constant. Since that’s what we’re trying to do here, let’s use the first two of those rules to see where we are.
Starting with the bore size change (Rule Two), going from a .300” to a .350” bore diameter (not groove) gives us about a 36% increase in bullet base area (.283 in² to .385 in²). That means we might expect about a 9% increase in velocity if all else remains the same. If a .30-30 conservatively gets 2200 fps with a 170-gr bullet, a .35-30 would get right at 2400 fps with a bullet of that weight.

However, here isn’t a .358” bullet of that weight, so we move to Rule One. A 180-gr bullet is about 6% heavier than a 170, so our wildcat .35-30 should get about 3% less, or 2330 fps. A 200-gr is 18% heavier than a 170, and ought to drop 9% of speed, getting 2000 fps.

So there you are. (And my initial “waguesstimate” wasn’t that far off!) Work up your wildcat until you hit 2300 fps with a 180-gr bullet, or 2000 fps with a 200-grainer, and you’ll be at about the same pressure as a normal .30-30 load. Which is certainly safe in your gun. In short, you did very well!

Thanks Rocky. That's EXACTLY the information I was looking for.
 

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I can't tell you what to look for but I can tell you not to expect anything useful from primers. They are the poorest "excess pressure indicatiors" available.
 

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BTW, I got the bore area numbers wrong (squared the diameter instead of the radius on both - duh) but the difference is still about 36%, so the end result is the same.

Badad, those three rules were not developed from theory. They were derived by working backwards from actual lab-tested load data. Your point about bearing surface is cogent, but is important only if you are significantly changing bullet type or shape as well as weight; i.e., if you go from a flat-base cup and core roundnose bullet to a boattail long ogive solid copper bullet, all bets are off.
 

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I have used Quickload for both new cartridges with no published data, and existing cartridges for less common loads.

I think if you carefully get all of the parameters in Quickload - especially the case capacity!! - then you have a pretty good shot (pun intended) to get a reasonable idea of the pressures. That, and you MUST run them across a chronograph as you work up to ensure that something isn't amiss.

There are other programs like Load from a Disk and the old Powley (?) calculator. The Powley calculator, if I remember right, is only for the single-based (IMR) powders. Single-based powders do seem to be fairly predictable for this sort of thing.

Rules of thumb per Rocky's post will help keep you out of trouble, as well. Just keep checking your results as you go.

Good luck, and kudos to you for thinking in terms of doing this safely.
 

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Between 2200 and 2300 FPS I would think ya got an awsome deer cartridge !!
I thought some one like rocky would find you .

Ranger 335v
Finding a spent primer blown out of the case , makes me think it is way over bored ,as one that looks more like a rivet head .
 

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"Ranger 335v Finding a spent primer blown out of the case ,"

IF we get a blown primer pocket. THAT'S that's our overpressure sign, not the primer itself.

Most "rivet head" primers are due to excessive head space. Instead of excessive pressure, it's more often caused by setting bottle neck case shoulders back too far. But it can happen in handguns too; sloppy revolver cylinders and pistol cases trimmed too short will do it.
 

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As far as loading wildcats is concerned we should always keep in mind about what we want with that which can be safely attained.

Basically if you can achieve 2150-2200 fps. as maximum with a 170 grain bullet, then a velocity of about 2050-2100 would be the max. for a 200 grain bullet.

Should you achieve 2050 - 2100 fps with a 200 grain bullet,, your Gun would be giving you it's all.

Your gains of another 50 - 100 fps. more in velocity aren't worth the risk to life or limb, much less the wear and tear on the fire arm it's self.

I've learned to look at it as similar to this.

My car can undoughtably go 120 mph.

Through just the same it's no where's near worth the risk to drive it that fast. Now thats not to say it wouldn't be fun for a minute or two, but if I were to to do it everytime I started up my car that would be a fools folley.

If you catch my drift.

Lever minded ....
 

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I can't tell you what to look for but I can tell you not to expect anything useful from primers. They are the poorest "excess pressure indicatiors" available.
Indeed.

A few years back I made up 5 pairs of rounds for one rifle, spanning the range from minimum to maximum loads. Afterward, I popped the primers out and arranged them in order from least flat to flattest. There was no correlation between flatness and powder charge.
 

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COTW - 12th Edition

35-30/30. (Paraphrasing) The 35-30/30 is one of the oldest known smokeless wildcat cartridges, with many 30/30 and 32WinSp rifle barrels being rebored to this cartridge after having been shot out. It has roughly 14% less case capacity than the 35 Remington. Both cartridges are actually capable of more performance than typical factory loads, but not in the relatively weak firearms for which they have often been chambered.

Please consider the loads below to be maximum; reduce by 10% and work up.

200gr JSP IMR4198 25gr 1925fps 1650ft/lbs
208gr Ld IMR4198 25gr 2895fps 1660ft/lbs
210gr Ld W630 15gr 1520fps 1080ft/lbs
245gr Ld H335 30gr 1770fps 1710ft/lbs
282gr Ld H335 28gr 1700fps 1810ft/lbs
292gr Ld W748 33.5gr 1620fps 1580ft/lbs
 

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The .35-30 is in Quickload, who'd a thought..... ?

However, the Quickload version shows a case capacity much closer to the .35 Rem than what other reference materials show. Regardless..... you would for sure want to fire-form some cases and check this out for yourself, before going on any predictive data.

Having said all that, I don't think that I would push much over 2,000fps - if at all. The factory Rem 200gr. RN ammo works quite well at muzzle velocities that seldom exceed 2,000fps.
 

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That's the problem. I don't want to get to BEYOND safe. I do have a chrony, but I was assuming that when a pressure spike was evident by velocities that I was again already past safe levels for the lever action. Meaning I didn't think velocity spikes would occur until you were at CASE maximum pressures, i.e. 60k psi or thereabouts, which is way beyond where I want to be with the rifle.
Levers have weak case extraction so when pressure starts to cause flattened primers and hard lever extraction you need to back off to where it extracts without trouble.
Providing the case was an easy fit before it was fired.
Even if primers are slightly flat but extraction is still fine then it should be ok.
Part of the good extractng lever is to size all cases for an easy no squeeze fit to start with.
 

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Evan,

Post your loads and barrel length and velocities and we can likely deduce your pressures reasonably well with QuickLOAD. Powders vary in burning rate from lot to lot, but their energy content stays fairly steady, so the program can be tweaked in burning rate to see what pressure it takes for a particular charge weight of a particular powder's energy content and other burning characteristics to be translated out to the actual velocity you are getting.

Also useful t know is the distance from your muzzle to your chronograph. I've seen complaints and witnessed misreadings from close sky screen positions and use 15 feet pretty much always now.

Your discovery that 4198 did best is not too surprising. 3031 can produce some top loads in .30-30, but as the bullet gets wider relative to the case diameter, the powder needs to be faster to make gas fast enough to keep up with the escaping bullet.

One more pressure sign for lever guns is to watch out for an increase in charge that causes a jump in the number of thousandths of stretch in the extracted case. That sudden length increase is due to the sides of the action stretching and letting the rear locking lug move back, opening the bolt a crack under the pressure. M. L. McPherson uses this to determine maximum loads in the Marlin actions. It's not a place I'd recommend going. Just something more to watch out for that is unique to rear lug actions.


Baddad457,

It turns out the difference in bearing surface doesn't have a proportional effect on friction. Friction between two sliding surfaces is a function of force perpendicular to the sliding. You multiply that force by the coefficient of friction for the sliding materials to get the resulting friction force to be overcome.

A portion of that friction in a gun is due to bullet spring-out pressing against the bore. If you were to force long and short bearing surface bullets of the same construction into a bore with a press, you'd feel the expected resistance difference to forcing them through it. That's because the longer bearing surface has more material compressed and so it applies more total outward spring force against the bore. Multiply that greater spring force by the coefficient of friction and you get greater friction.

However, the dynamics in a firing gun are a bit more messy. Spring-out friction is only a portion of the total friction and is something lower than the force needed to start a bullet into the bore. Harold Vaughn estimated it to be on the order of 600 lbs. Most of the friction comes from propellant pressure upsetting the bullet bearing surface against the bore as it accelerates the bullet. That's why, if you look at a fouled barrel with a borescope, assuming a uniform bore, you see the majority of the metal fouling build up in the first couple inches of the throat. That's where the bullet bearing surfaces were when the chamber pressure peaked and the upsetting force was at maximum, creating maximum friction.

The upsetting force is due to the pressure difference between the breech and muzzle ends of the bullet. Like any cylinder subjected to a compressive force difference across its ends, the bearing surface swells outward in the middle in response to it. That's what produces the majority of bullet friction in the bore.

Unlike the additive effect of spring-out friction with added bearing surface length, if the loads for the two bullets are adjusted to have matching chamber pressure, the friction force due to upsetting the bullet will be the same. That's because the difference in pressure across the long and short bullets is the same. The longer bullet divides that swell over more surface area giving less friction per unit area, but the same total upset friction. The bottom line is, the total friction from a longer bullet bearing surface is not as much larger as you'd expect.
 

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Discussion Starter #20
COTW - 12th Edition

200gr JSP IMR4198 25gr 1925fps 1650ft/lbs
This is the load data everyone has and seems to be the only published out there for this cartridge.

That said, I don't know what in the world their test conditions were because I found that to be WAY off on velocity.

I based my decisions on test loads on comparing data for several similar cartridges (.35 Rem, .375 Win, 32 Win Spec., 30-30 Win, etc.)

Using logic similar to what Rocky described, I decided that getting to 2000 fps with the 200 gr core Lokt should be attainable and safe and started working in that direction.

I started with H4895 as that is my favorite all around powder. It quickly became obvious that 1900 fps was going to be it without a HEAVILY compressed charge.

Next was IMR 3031. Same deal 1900 fps was about all it had in it.

So I went to H4198. Using 35 Rem. data I loaded starting charges and worked up the loads until I got 2000 fps.

The charge was 31gr of H4198 producing 2035 fps from a 20" barrel with the Chrony at 12'

1 gr increments had been giving about 100fps of increase until I tried 32gr which only jumped to 2050 fps so I stopped.

I realize I am over published data, but there was no indication whatsoever in any load I fired of sticky extraction, primer signs, case issues, etc.

If somebody has Quickload and can run the numbers and tell me I'm an idiot in danger of losing my fingers then I will certainly back off the charge. But logic seems to say everything is on the up and up.

Opinions?
 
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