Help with PSI Load data

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Tooweels posted this 11 January 2017

Hello guys , Im using a RCBS 45-340 U Mould for my 1886 Winchester 45/70, load I've used is 30 grs ADI AR 2207 (4198) which shoots well but Im wondering if anyone has published load data for same but with Chamber pressure in PSI not CUP`S ? ADI and Hodgden websites both list CUP`s only and I don't have access as of yet to any of Lymans cast manuals, alloy used is range scrap with Brinnel of 12.5 or according to Lee`s Brinnel scale 16k strength

Thanks

Steve

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onondaga posted this 11 January 2017

Tooweels

 

If it is pressure safety you are concerned with Lee has relatively close data* in psi for a slightly heavier 350 gr cast bullet in 45-70 modern rifles. MAXIMUM 56.0 gr H4198 reaches 2300 fps @ 50,000 psi. your lighter bullet will have less pressure at the same charge and 50.5 gr is recommended START with 2091 fps. A 10 gr weight difference with cast bullets in this weight and caliber has nearly zero effect on pressure or velocity. Do not substitute IMR 4198 or your 2207, pressures are not equal but the recommended START is safe for the IMR or H 4198. Hodgdon specifically states not to use H4198 below recommended START level as ignition problems can be dangerous. There are much better igniting powders to go lower, IMR Trailboss will go much lower very safely.Following IMR general directions for Trailboss will not over-pressure your rifle.

The same Lee book also has a formula for calculating pressure change with charge reduction that is very accurate. If you run spread sheets well, you will eat up the Lee formula and spit out graduated data. A calculator is very time consuming but will work for the short span algorithm. Short span means the farther you are from base data you are the greater the error of the spreadsheet or calculator results. Safety tells me not to use the algorithm hotter than10% below MAXIMUM

 

* p.692, Modern Reloading Second Edition, Richard Lee

 

Also there is a formula for converting CUP to PSI but it is only accurate to +- 3000 units:

 

CIP/CUP units

(CUP x 1.20911)-2608.88 = ANSI psi within 3,000 units  DO NOT USE THIS FORMULA ANYWHERE NEAR MAX.

 

WARNING !!!!!!!!!   If you don't understand this stuff like a math teacher, don't risk your life.

 

Gary

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Tooweels posted this 11 January 2017

Hi Gary

         Thanks for taking time to research and show me your efforts, I apologise that I did not list my Mould correctly it is RCBS 45-325-FN -U, Bullets drop at 336grs My Rifle is Miroku built 2016 model of 1886 Winchester and though a strong action will limit the loads I use to Trapdoor level only for various reasons and mostly starting with my shoulder hahah.

I've used the formula you provided above and got this 14400 x 1.20911 = 17411.184 - 2608.88 = 14802.304

So if Im correct the chamber pressure will be close to 14802 psi if 14400 CUP was a provided published load data, do you agree?

I've tried Trail boss powder a few years back and although light on the shoulder always had bad leading just past the throat and believe it was due to the high peak pressure upon ignition also the velocity was only around 1000 fps which made the bullet get pushed around in windy conditions 

Thanks again Gary have a good day

 

Steve

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onondaga posted this 11 January 2017

Steve,

Your math is good, just remember the  error factor and that the pressure is anywhere within plus or minus 3000 psi of your answer and the formula is no more accurate than that. This is because between CUP and psi, one is a measurement of peak pressure and one is average pressure. That is the reason for the +-3000 units error factor.

I believe you are incorrect about the pressure limitation on your 2016 Miroku 1886 Winchester. It is built to easily handle the pressure of any current manufacture 45-70 commercial lever action ammunition and that is well above trapdoor load level. Check your owners manual online if you don't have one and you will see that factory level  loads are fine for your rifle.

Current loading manuals have 3 load levels for 45-70, they are Trapdoor, Modern Lever Rifles and modern single shots. Any of the modern Lever Action 45-70 loads are safe for your rifle. The 2016 Miroku 1886 Winchester is not a wimp that only handles Trapdoor load levels.

Also note the Lyman cast bullet manual recommends BHN 15 #2 alloy for lever action 45-70 loads and this means your current BHN 12.5 scrap alloy has insufficient strength for 45-70 lever action loads.

 

I mix a recreational BHN 15 alloy with soft range scrap recovered from jacketed bullets and Linotype scrap at 1:1 ratio and it consistently tests BHN 15 as cast and air cooled. For hunting bullets I get Rotometals certified Lyman BHN 15 #2 alloy: https://rotometals.com/bullet-casting-alloys/

 

Gary

 

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Tooweels posted this 12 January 2017

Hi Gary, thanks for all info much appreciated

 

Steve

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Ken Campbell Iowa posted this 12 January 2017

hah... i remember shooting a steel butt plate browning 1886  45-70 with a full load and 500 gr bullet ... back about 1992 ... i think it was two shots .... not since tho ...

i do like those big bullet holes ...

ken

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onondaga posted this 12 January 2017

 Tooweels

The Lyman Cast Bullet Handbook 4th Edition specifically lists the MAXIMUM pressure for the 1886 Winchester at 28,000 CUP. Your ADI load at 14,400 CUP isn't even close to MAXIMUM for your rifle. If you are going to kill stuff with the rifle a good 45-70 lever rifle deer load is built around providing at least the humane harvest deer load level of 1,000 foot pounds at 150 yards. The 1886 is designed to do this with near a 400 grain cast bullet. A lighter bullet will have to go faster to deliver the same energy and it will kick the same. You may well get the rifle to shoot well with your light bullet but the 45-70 Gov. cartridge and your rifle are specifically designed for ~400 gr cast bullets. That 150 yard Deer Humane Harvest level load is close to top end for your rifle with any bullet weight. You can figure foot pounds on impact at any range from your bullet weight and any muzzle velocity here:

http://www.handloads.com/calc/index.html

 

Gary

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Larry Gibson posted this 12 January 2017

 Toowheels

 

If you want to send me some (30) of your 45-70 bullets as you shoot them (sized, lubed and GC'd) with complete load info (case, primer, OAL. powder, powder charge)  I can duplicate the load and actually pressure test them.  Then you will know not guess.

 

PM me for address if you want to.

 

LMG

Concealment is not cover.........

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Tooweels posted this 12 January 2017

Hi Gary

           Thanks for info on site, I do have 385,405 and 420 gr pills here that were made commercially and can use those for tipping over deer also some Copper jacket Hornady hollow points that I loaded once with a full house load and don't think I will go there again !

The main reason I bought the RCBS mould was so I could shoot the gun a lot without becoming recoil shy and secondly the guns short throat meant that I had to either use short Hornady cases to use the crimp groove on the commercial bought bullets I have or seat them deeper on my Starline brass, the RCBS light bullet seats nicely in the 2.1 cases and chambers with about .0025 jump

Thanks and regards

 

Steve

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Tooweels posted this 12 January 2017

Hi Larry

              Thanks for kind offer but will gracefully decline as may be a bit difficult shipping to US from New Zealand

Have a good day

 

Steve

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Larry Gibson posted this 12 January 2017

I was afraid you lived down there somewhere......unfortunate.  Perhaps someone else up here has the same mould and can ship me some?  I can size, GC and lube.

 

LMG

Concealment is not cover.........

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Mike H posted this 12 January 2017

I am not one to worry too much about knowing exact pressures,so long as reasonable loads are used.

The ADI Handloaders Guide has a section for single action shooting,there are any amount of loads with lead bullets,admittedly the pressures are in CUP,not PSI.Of interest is Trail Boss loads giving higher pressures and lower velocities than H4198.Of course one would need to balance cost of powder and accuracy with the desired velocity.

Mike

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onondaga posted this 12 January 2017

 Tooweels

Here is an example of what I am saying. Take your 405 gr in 45-70. The start loads in all the recommended powders are all well above the 405's humane harvest load level of 1240 fps yielding 1,000 foot pounds at 150 yards. The only powder in the group that is Hodgdon recommended to be safely reducable to 50% available case volume is H4895. That powder isn't popular in 45-70 although it is recommended. In this application H4895 burns less completely and dirtier than many powders, but it is consistent and accurate, The start load is 50 grains with 1614 fps. and is a shoulder dislocation. The case capacity with the bullet is 55 gr H4895, so you can safely go down to 27.5 grains. Charge reduction software gave 1240 fps a charge of 36.0 gr H4895. An ink verified slip of your bullet with a dummy load is the best fit you can get with cast bullets, my rifle needs a .461” cast bullet to fit best..

The 1240 fps loading of the 405 gr with 36 gr H4895 is well within Hodgdon recommendations and the  load has a mild recoil while being brutally lethal to deer out to 150 yards. People that prefer flatter trajectories go way beyond needed humane harvest level loads. Personally for me, I get more satisfaction knowing the trajectory of a load that I can easily and comfortable shoot well in a big bore rifle. This mild 45-70 load  will kick less than lever rifle Factory 30-30 loads and kill Deer better at the same ranges of a 30-30.

 

50 shots at the range wont hurt you with this load and it is a very inexpensive load when you cast your own.bullets. That is going to be an accurate load on the first try if your cast bullets fit well. It will be easy to get used to as the only load you need in 45-70 with a well available powder. Verify your exact bullet weight with a scale and your velocity with a chronograph and then energy calculations are spot on.

 

Gary

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onondaga posted this 13 January 2017

The best fit for any cast bullet load is determined easily with an inked bullet dummy load for a slip fit on the front driving band. Most commercial molds cast too small for 45-70 lever rifles but the Lee Aluminum molds are easily honed and great custom molds are available. Mine is honed to drop #2 alloy at .4615” and I size check at .461” for a verified slip fit for my particular rifle. It will put 10 shots under 1"@50 yds. That is all the accuracy I ask of a big bore with a Deer hunting load.

Gary

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Tooweels posted this 13 January 2017

Hi Gary

             Your exactly right about the 4895 recoil being moderate, I used its close equivalent ADI AR2206H a lot in my Pedasoli Sharps 45/70 and the same load almost, 36.5 grains gave me 1300 fps with 32'' barrel and 420 grain bullet, lots of crumbs in the barrel after each shot though but not the end of the world, I used it only shooting targets though and at 200 yards best group for me was around 5-6'' off sticks, a lot of that too could be operator error never locked it down on a bench, I've got some here will fill up some cases and try it in the '86

All the best

Steve

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onondaga posted this 13 January 2017

Steve,

I hope you get the Hodgdon powder, it is worth it for the ignition quality in Hodgdon recommended reduced loads for H4895 specifically. Crimping also improves ignition with H4895 with cast bullet reduced loads. The crimp holds the bullet a little longer during ignition. I get consistent results using a Lee FCD specifically set to crimp .005” smaller than sized case mouth diameter. Roll crimps damage the bullet more and don't hold as well for slower powder like H4895 reduced big bore loads. I do the Lee  Factory Crimp in a separate last step and previously have the bullet seating die not set to roll crimp at all. Inside case mouth over chamfer ruins crimp consistency, don't chamfer more than 1/4 brass edge thickness and check case length after every sizing.

You sound acquainted with the caliber, I hope you get the '86 shooting great with a comfortable load.

 

Gary.

 

Gary

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Tooweels posted this 14 January 2017

Thanks Gary, will let you know

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onondaga posted this 15 January 2017

Steve, neither this site or gmail verify my response to your PM about the 500+ gr bullet seating for lever rifles. Start loads will not over-pressure with a heavy/long bullet seated for a START load in a lever rifle. Any hotter and you need to be a genius at reading pressure signs for every shot.

Gary

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