Pressure signs on straight wall cases?

[Lonewolf74]

I've done some various load work up in my Marlin 1895 guide gun in 45-70 and I was wondering if this casing will show typical pressure signs such as flattened primers and bolt marks on the head? Or are there other things to watch for due to the straight wall case design?

I've run up to 60 grains of RL10x which is considerably over book max with zero pressure sign. I know the rifle design is much stronger than what published data is for and the cartridge can be loaded very hot compared to published data but I want to make sure I'm keeping an eye out for the right things and not flirting with the line and not knowing it.

 

[Buck Buster]

I think you have it, the action should open harder with the increase of pressure and the primer will start to get a burr on it around where the firing pin comes in contact with the primer. Don't go over max loads, and work up to them .5 grain at a time from about 4 grains below max. Make sure the gun is in good condition first. Good luck hunting and be safe.

 

[g0rd0]

preasure sings can be hard to read. A sure sign of high preasure is pierced primers, then there is spent primers that look like a top hat. But, when all else fails and this can happen after you purposely over load a bust chamber.
Don't exceed max book loads, it is just not a good idea

 

[Buck Buster]

You will see signs of pressure long before your primers have those kind of signs. Like I said it will start with a minimal burr around where the primer strikes , examine with a magnifying glass if your eyes are bad but you can even fell them with a finger nail or a point of a needle ect. Pierced primers mean you have gone way too far already. That's why you start below maximum and work up in small amounts of powder increases. Good luck hunting and be safe.

 

[Lonewolf74]

So if you get to max or slightly above you will get flattened primers and a sticky bolt/action just like any bottle neck case?

 

[Buck Buster]

Those are the signs that will be the first showing pressure is getting towards the upper limits. Straight cases still expand to fill the chamber of your gun, the more the pressure the tighter the fit . This tight fit makes the action stiff to open. In my 308 & 300 mag. rifles ( not straight cases ) I try to get the most speed out of them that I can to get them to shoot their flattest for long range hunting & shooting so I load them up till I start to see these signs of pressure then back them off about a half of a grain. Some guys push them till the primers start to actually become rounded when they set them down base first they actually will rock around. To hot for me , and a 45-70 is no long range gun so I would not have a reason to push them as far as I do my magnums. Better safe than sorry, take your time and think about what your doing you will be ok. Good luck hunting and be safe.

 

[bigedp51]

Below will not tell you chamber pressure, it will simply tell you the strength of the cases you are using. Example Lake City brass is harder than commercial brass with Lapua coming in second as far as hardness. "BUT" the flash hole web "thickness" adds radial strength to the base of the case making it stronger.

Simple Trick for Monitoring Pressure of Your Rifle Reloads
http://www.hodgdonreloading.com/rel...-trick-monitoring-pressure-your-rifle-reloads

"One of the first rules of handloading is to always follow the approved reload data. The cautious reloader gradually works up to approved maximum loads to ensure his particular gun does not show pressure signs. Generally this is visual observation of the fired shell case head and primer. There is another slick way to check for pressure signs if you are interested.

Using a blade micrometer that measures in ten thousandths (.0001"), new, unfired cases can be gauged before and after firing to determine reasonably accurate maximum loads. Micrometers measuring in thousandths (.001") are insufficiently accurate to perform these measurements, and should not be used. Previously fired cases cannot be used accurately due to various levels of brass hardening. Measurement is taken just ahead of the extractor groove on the case head and must be taken at the same place on the case before and after firing. By placing a small mark on the case head – entering the cartridge in the chamber with mark at 12 o'clock – a consistently accurate measurement can be taken with each firing.

Lower pressure rounds, like the .30-30 Winchester, usually yield maximum pressures at .0003"-.0004" expansion. Modern cartridges, like the .223 Remington, will show maximum pressure at .0004"-.0005", while .308 Winchester, .270 Winchester, etc., typically yield .0005"-.0006" expansion at max pressure. Magnums, like the .300 Winchester Magnum, show maximums at .0006"-.0007" expansion, and should be measured on the belt.

In conjunction with these measurements, case head signs of pressure should be monitored as well. These signs include very flat primers, slightly cratered primers, ejector marks on the case head, and stiff extraction. All these case head signs indicate high pressure, and loads should be reduced until these signs disappear.

As always, start with the beginning load listed, and cautiously work up to the maximum shown for that set of components, using the methods listed herein."

Example below and why Federal brass has over sized primer pockets sooner than cases with thicker flash hole webs. So again measuring base expansion doesn't tell actual chamber pressure, but it does tell you when you are pushing that brand of brass to hard or beyond its elastic limits.

 

[Buck Buster]

You should always keep your brands of brass together, I buy loaded shells shoot them then keep them in their rightful boxes. They may show max pressure at different points. I have so far not found I had to use a different load for my different types of magnum brass, Federal , Winchester, and Hornady . I don't measure my cases like it says in 51 s second and third paragraph, because I fire form my cases to fit the chamber tight and I only neck size the cases; this puts most all of the energy behind the bullet to get maximum velocity that I told you I was after for flatter shooting. What I do is basically in the last three paragraphs , my bolts do work a little stiff due to near maximum loads and only neck sizing. My father loaded for 60 years not taking the measurements stated above, nor have I for the 32 years that I have had to carry on the reloading for the family. Our smaller deer cartridges 222, 270, 30-06, 30-30, ect. we always full length resized and often mixed the types of brass, they all seemed to shoot about the same about min of angle. We never pushed these like I do the magnums, always under the manuals maximum loads. Again these are like the 45-70 in the way that they are mainly close range under 200 yard guns. In the total of our 93 years of reloading we only had one problem, probably back in the early to mid. 1960 s my father got a bad bunch of primers for the 222. We ended up shooting all that would go bang and I think my father buried the ones that didn't. Today I would pull the bullets and save the powder and probably not try to save the cases. Good luck hunting and be safe.

 

[LoneTraveler]

You did not state the bullet weight you are using?
Hornady 7th Edition list 3 different loads for 45-70 Gov.
One for Trap Door rifles,
2nd for Marlin 1895, They only list RL-7 with 350 Gr. bullet.
3rd for Ruger No. 1
All loads are for Hornady 300 and 350 Gr. Jacketed bullets.

 

[WildRose]

I've done some various load work up in my Marlin 1895 guide gun in 45-70 and I was wondering if this casing will show typical pressure signs such as flattened primers and bolt marks on the head? Or are there other things to watch for due to the straight wall case design?

I've run up to 60 grains of RL10x which is considerably over book max with zero pressure sign. I know the rifle design is much stronger than what published data is for and the cartridge can be loaded very hot compared to published data but I want to make sure I'm keeping an eye out for the right things and not flirting with the line and not knowing it.

Another is the print on the headstamp will noticeably change with too much pressure, it will start to look as though it wasn't stamped deeply enough originally.

The rim will also noticeably thin and get larger in diameter.

 

[WildRose]

Those are the signs that will be the first showing pressure is getting towards the upper limits. Straight cases still expand to fill the chamber of your gun, the more the pressure the tighter the fit . This tight fit makes the action stiff to open. In my 308 & 300 mag. rifles ( not straight cases ) I try to get the most speed out of them that I can to get them to shoot their flattest for long range hunting & shooting so I load them up till I start to see these signs of pressure then back them off about a half of a grain. Some guys push them till the primers start to actually become rounded when they set them down base first they actually will rock around. To hot for me , and a 45-70 is no long range gun so I would not have a reason to push them as far as I do my magnums. Better safe than sorry, take your time and think about what your doing you will be ok. Good luck hunting and be safe.

When the primers start to back out flat to the case head and flatten you've already tone too hot. They will get to where it's almost impossible to tell where the margin is between the primer and brass as though the brass was poured around the primer or the primer was poured into the case.

Any further than that and you're risking serious damage to your rifle and yourself.

 

[Lonewolf74]

You did not state the bullet weight you are using?
Hornady 7th Edition list 3 different loads for 45-70 Gov.
One for Trap Door rifles,
2nd for Marlin 1895, They only list RL-7 with 350 Gr. bullet.
3rd for Ruger No. 1
All loads are for Hornady 300 and 350 Gr. Jacketed bullets.

300 grain nosler (combined technology). I cross referenced several sources to get a starting point with my combo.

 

[Lonewolf74]

Thanks for all the input guy's! And just to clarify I know very well what typical pressure signs are and scrupulously examine cases while doing load work up. I was just wondering because of something I read if it's possible a 45-70 (or similar case design) would not show typical pressure signs for some reason or another.

 

[Lonewolf74]

Buck Buster my 45-70 is my short range brush gun but it's perfectly capable out to 300 yards and beyond if is ever needed. I want to be ready for when that is needed and not have a ridiculous drop.