I am within striking distance of finishing my Krag 35/40 sporter. Looking at starting loads for 308 W with heavy bullets sometimes they are right at 40K CUP and the same powder in a Krag at 40K CUP (was PSI)  shows the same charges with Varget. My go to powder has been Varget for some time and Hodgdon shows;
46 grains at 42,800 CUP load for the 358W with a 220 bullet
45 Grains at 40700 CUP load for the 358W with a 225 bullet
34 grains at 27800 CUP load for 35Rem with a 220 bullet
38 grains at 33300 CUP load for 35 Rem with a 220 Bullet
Hodgdon does not seem to be worried about detonation with low pressure loads in the 35Rem with Varget.
Lyman's reloading book had very similar data for 30/40 308W and 358W. I will have to borrow my son's Lyman book to verify.
So the question is does 40 grains as a starting load and 45 grains as a maximum load sound reasonable for Varget in a 35/40? One advantage of using loads like this in Varget, there will be no chance of getting an accidental double charge.

I would be very careful of any load that exceeds 40,000 cup!!!  If you are using the Lyman book, stick to established loads.  A lot of us use 40.0 grains of 4350 with our 220 GR bullets.  4350 is a nice slow burning powder which approximates the original .30 US round very nicely.  There is also virtually zero chance of a double charge, as the case is more than 3/4 full with the 40 grain load (a double charge would mean that you're spilling powder all over the bench, LOL). 

Mr. Steinmayer's advice is correct.  The action is a Krag, not something chambered for .308 or .358.  40.0 grains of IMR 4350 pushes a 220 grain jacketed .30 cal bullet at something approaching the velocity of the original Krag cartridge. 

If you use the same 40 grain load in a Krag case opened to .35 caliber, and you are pushing a 220 grain bullet, the peak pressure will be about the same, but pressures will drop quicker because the gas is escaping from a tube that has a bore cavity of greater capacity.

Just got the Lyman book and it has 358W starting load for 220 grain bullets and Varget powder:
47 grain 36,200 cup with a velocity of 2278
That makes Hodgon's 45 grains look like a reduced load.
The Hodgdon 225 grain bullet with 45 grains got a velocity of 2254 fps.  2200FPS is what I was hoping for when I started this project. About 1/2 way between 35Rem and 358W.
Lots of interpolation and guess work going on here on my part. Is a 40K CUP load in 358W the equivilant of  a 35/40? A definite maybe I guess. Maybe it depends on whose pressure barrel.
I may end up proofing at 47 grains and using whatever between 40 and 45 grains gives the best accuracy.

On another issue, is everyone else having to get a new password every time you log in?

If you are necking the 30/40 case to 35 caliber you are making a 1/10 in short 35 Winchester case.  Not sure how much 35 Winchester data is still around (let alone pressure tested) but you can use the starting load data as a guide.  The 35 Win was used in the 1895 Winchester lever and had a working pressure of about 45K psi vice the 40K psi for a Krag.  The case capacity comparison given for 358 Win and the 30/40 makes them seem very similar, but the data I have seen is based on the case filled to the mouth, meaning the actual powder space in the Krag is a lot less than in the 358 and probably a lot closer to 35 Rem.  The ballistic of the 35 Win, at a slightly higher pressure level are only slightly better than the 35 Rem. Before betting any body parts it is good to remember that even the newest Krag action is over 110 years old.

Extrapolating data from one cartridge to another of the same bore size depends largely on case volume.

Usable capacity (meaning volume with bullet seated to magazine length) of the .30-40 case is some 2 to 4% greater than that of the .308 Win. case. The same, of course, applies after they are necked up to make the ".35-40" and the .358 Win. The .35 Win. has a usable capacity about 25% more than the .358. Consequently, a reasonably high-density load generating a given pressure in the .358 will yield about 2-4% less in the .35 Krag and one developed in the .35 Win. gives ~25%+ higher pressure in the smaller Krag or .358 case.

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Note how 46 grains Varget in .358 gives same velocity but significantly higher pressure than 50 grains in relatively large .35 Win. case.

QuickLOAD estimates - NOT LOAD RECOMMENDATIONS!

FWIW, you can take any data or advice Para offers to the bank!  And, as Rich stated, regardless of the barrel used, the action is still a Krag action. 

Parashooter,
The 35Win is so far off on volume and no current data was the reason I disregarded it. The closeness of data for the 308 starting loads and 30/40 max loads made it seem like a better choice for "extrapolating" data. 2-4% less expected pressure  in the Krag sounds good also.
The pressure curve you posted is in PSI not CUP. Would 51K PSI correspond with Hodgdon's  42.8K CUP?
If so, using 45 grains as a max safe load and looking for an accurate load in the 41 to 44 grain range will be the plan.

Rich, Losing body parts does not sound like fun, if I use Lyman's 47 grains as a proof load it will be with the gun wrapped in a towel, tied to an old tire and the trigger pulled with a string.

Fred, what will most probably happen is that the bolt lug will crack.  That happened (and continues to happen) to many Krags simply by overloading the powder pushing the 220 grain bullet. I did it to my Krag with 41.5 grains of 4350.  Someplace on this site is a link leading to Michael Petrov's experiments in blowing up a Krag.

That said, I have seen Krags converted to both .35 Winchester and .405 Winchester.  The magazine must be modified to take the slightly longer cartridge.

Ken Water's Pet Loads book has chapters on all 3 cartridges; .30/40 Krag, .35 Winchester and .358 Winchester. Walter's work is well worth reading, especially the part about asking too much of old rifles.

My goal is to stay below the 40K cup, the problem is using the best interpolation as to what is 40K in 35/40.
Here is what happens from Lyman when going from 308W to 358W with varget maximum loads:
308W  42.5 G 2503 FPS, 60.2K PSI 200 grain bullet
358W 51G     2612 FPS   45.5K CUP 200 grain bullet
I wish both were in CUP
Hodgdon's published maximum loads for 308W and 358W
308W 42 G 2441 FPS 50.1K CUP 200 grain bullet 24 in barrel
358W 51 G 2527 FPS 47.7K CUP 200 grain bullet 26 in barrel
Same thing happens with 06 and 35 Whelen charge weights go up and velocity increases with the same weight bullet, while pressure decreases.

Roughly 20% increase in going from 308W to 358W but the powder may act differently at 308 pressure levels.
I  expect the same thing when going from 30 caliber Krag to 35 caliber Krag. Just how much though?!?!
When I had this action apart I did a touch up lapping of the locking lugs just to make sure I had near 100% contact and found the guide rib was also in contact.

FredC wrote on Oct 29^th, 2015 at 12:29pm:

. . . The pressure curve you posted is in PSI not CUP. Would 51K PSI correspond with Hodgdon's  42.8K CUP? . . .

As can be seen in the chart posted below, there is no accurate way to correlate piezo-transducer (psi) and copper-crusher (CUP) pressures. There are just too many variables affecting results in different cartridges.

What I can tell you is that QuickLOAD pressure figures are calculated to correlate with CIP piezo standards, which give these "Pmax" ("MAP" in US terms) figures -

.30-40: 47137 psi
.358W: 58740 psi
.35 W: 44236 psi

If you want to use QuickLOAD to estimate loads for your .35 Krag, measure the difference in weight between an empty case and the same one filled to overflowing with water. That will yield a maximum volume from which QL will calculate usable volume for any given bullet and seating depth. Results will still be guesswork, but a bit more "educated".

Table from a 1987 Hercules data brochure, using SAAMI MAP figures -

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Here's sample QL output for .358 with maximum H20 capacity adjusted to 60 grains and Pmax set at 47137 psi. PLEASE remember this is only a software estimate and may be very different from what happens in your rifle with your loads.

Cartridge          : .358 Win. (@ 60.0gr H2O overflow capacity)
Bullet             : .358, 250, Hornady SPRN 3525
Cartridge O.A.L. L6: 2.780 inch or 70.61 mm (seat depth 0.334")
Barrel Length      : 25.6 inch or 650.2 mm
Powder             : Hodgdon VARGET

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.087% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
%       %    Grains   fps   ft.lbs    psi    psi      %        ms

-10.9   89    41.00   2054    2341   32668   4709     91.2    1.630
-09.8   90    41.50   2077    2395   33728   4776     91.8    1.607
-08.7   91    42.00   2101    2450   34822   4842     92.3    1.585
-07.6   93    42.50   2124    2505   35953   4907     92.7    1.564
-06.5   94    43.00   2148    2560   37121   4971     93.2    1.542
-05.4   95    43.50   2171    2617   38329   5034     93.7    1.521
-04.3   96    44.00   2195    2674   39577   5095     94.1    1.500
-03.3   97    44.50   2218    2731   40867   5155     94.5    1.478  ! Near Maximum !
-02.2   98    45.00   2241    2789   42201   5214     94.9    1.458  ! Near Maximum !
-01.1   99    45.50   2265    2848   43583   5272     95.3    1.438  ! Near Maximum !
+00.0  100    46.00   2288    2907   45012   5328     95.7    1.418  ! Near Maximum !
+01.1  101    46.50   2312    2967   46490   5383     96.1    1.398  !DANGEROUS LOAD-DO NOT USE!
+02.2  102    47.00   2335    3027   48021   5436     96.4    1.379  !DANGEROUS LOAD-DO NOT USE!

Here's a link to Michael Petrov's experiment:    (You need to Login

Thanks for the link.  I read all 4 pages.  At least three of those who posted (Michael Petrov, "J.D. Steele", and Mark Beneson have passed on.  All three are sorely missed.

Since it is OK to link to Double Gun this is what got me started down this road a couple of years ago:
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Looking through this thread I saw a reference to 35 krag loads but in recent searches I have not been able to find anything.
Parashooter,
I had already researched the PSI/CUP conversion and found it was not possible to do consistently.
On your chart with the software estimate pressures it has a 250 grain bullet and not the 220 grain I intend to use. Is that correct? If so then 45 grains of varget with a 220 grain bullet should really be in a safe territory. Even if I could get more I like the idea of a moderate charge as there will be less operator punishment and noise.
I have also given some thought to this apparent equality of the 308 30/40 at 40K cup and thought about the difference in the shoulder angle. This will become less of a difference with 35 caliber as there is a lot less shoulder remaining. I have a 308 case somewhere I will try to find it and open it up to verify.
Reincarnated,
You mentioned cracking a bolt with 41.5 grains of 4350? My son's Lyman book shows a load several grains higher at 40K from a pressure barrel. I know different guns will make different pressures with the same load, but I have a theory why some of these old Krags may be developing more bolt thrust with what should be safe loads.
On the barrel that I took off this gun the chamber was .010 oversize for some distance from the rim. Could it be the case can not swell enough at that point to grip the barrel and allows the case to stretch and slide back with too much thrust on the bolt?

FredC wrote on Oct 30^th, 2015 at 2:54pm:

. . .On your chart with the software estimate pressures it has a 250 grain bullet and not the 220 grain I intend to use. Is that correct? If so then 45 grains of varget with a 220 grain bullet should really be in a safe territory. . . I have also given some thought to this apparent equality of the 308 30/40 at 40K cup and thought about the difference in the shoulder angle. This will become less of a difference with 35 caliber as there is a lot less shoulder remaining. . . I have a theory why some of these old Krags may be developing more bolt thrust with what should be safe loads. On the barrel that I took off this gun the chamber was .010 oversize for some distance from the rim. Could it be the case can not swell enough at that point to grip the barrel and allows the case to stretch and slide back with too much thrust on the bolt?

1. If you want more precise estimates from QL, you have to provide the overflow water capacity, as suggested earlier. Please note that I'm just providing examples of what you could do with QuickLOAD.

2. Shoulder shape/angle has been consistently demonstrated to have negligible effect on pressure with normal loads of conventional components in cases of equal volume.

3. Chamber .010" over case body diameter is completely normal. SAAMI minimum cartridge base: .453", maximum chamber base: .464". This has no practical effect on case/chamber adhesion or "bolt thrust".

"1. If you want more precise estimates from QL, you have to provide the overflow water capacity, as suggested earlier. Please note that I'm just providing examples of what you could do with QuickLOAD."
How is overflow water capacity obtained? I would think it would be with the water capacity of the case with the bullet installed? I am thinking I would pop the primer and fill a case with the bullet installed using a hypodermic through the primer hole, then compare before and after weights? I have a digital scale with .0005 lb increments or a power scale that measures  to .1 grain.

"2. Shoulder shape/angle has been consistently demonstrated to have negligible effect on pressure with normal loads of conventional components in cases of equal volume."
This means Roy Weatherby was a snake oil sales man? I sorta figured that

"3. Chamber .010" over case body diameter is completely normal. SAAMI minimum cartridge base: .453", maximum chamber base: .464". This has no practical effect on case/chamber adhesion or "bolt thrust"."
Learn something new everyday, thanks. Hope I can remember it all.

Posted earlier:
"If you want to use QuickLOAD to estimate loads for your .35 Krag, measure the difference in weight between an empty case and the same one filled to overflowing with water. That will yield a maximum volume from which QL will calculate usable volume for any given bullet and seating depth."

Trying to clarify the procedure -
1. Take an empty case with a spent primer in it.
2. Weigh the case on your powder scale.
3. Fill the case to overflowing with water.
4. Weigh it again.
5. Subtract the empty weight from the water-filled weight.
6. Using the density of liquid water as a constant, QuickLOAD converts its weight to volume (in cubic centimeters).
7. QuickLOAD calculates the volume occupied by the seated bullet and subtracts that from the overflow volume to yield the remaining volume.

Parashooter,
This is what I got on capacity of the case:
60.9 grains of water
It turns out the bullets in hand are 200 grain Sierra round nose, bullet number 2800. These bullets have a .290 inch measurement from the base to the center of the cannalure if that is needed.
I will probably use 220 grain in the future.
Is your QuickLOAD program still available and what is the learning curve like?
Thanks
FredC

QuickLOAD/QuickTARGET version 3.9 is supplied with a comprehensive "USER FRIENDLY" MANUAL included on the QuickLOAD CD-ROM disk.   (You need to Login

$152.95 plus S&H

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Parashooter,
Thanks. My copy should be here today.

Anyone,
Just started reassembling everything and the loaded cartridge now sits level when in the position to be pushed into the chamber. I drop the same cartridge into my original Krag and it is pointed up and feeds normally. The only thing close to a modification on this sporter since I started, was to polish some bugged up spots inside the sideplate. Is there a way to assemble the cartridge pusher wrong or did the polishing mess things up? This sporter was apart for 2 years with most of the pieces in a drawer till now, it did feed normally before I started.

Experiment and try switching Krag side-plates to see if they function differently in positioning/feeding your .35 caliber cartridges.

Thanks Butlersrangers.
I had swapped side plates with just a little difference going both ways. Part of the problem was I was experimenting with out the action fully assembled. Leaving the magazine cutoff out causes major problems as well as causing damage to the rims.
After figuring that out I did some minor polishing on the upper region of the side plate, as well as enlarging the ID radius leading into the chamber. Not perfect yet but I have a plan.
I made up some dummy 308 cartridges of what was used before the conversion and they did not feed that well either, I had just not noticed.

Hello Parashooter.
I have been running this QuickLoad today and to see if it was acting right, I ran the earlier mentioned 4350 loads with 220 grain bullets in 30/40. With the 41.5 grains mentioned that cracked a bolt Q/L shows that is under the 47,137PSI safe value but unknown tolerances may cause dangerous pressures! With 40. grains of 4350 it suggest to check loading manuals because secondary explosive effects are possible.

Switching to 35/40 it shows 47 grains of Varget to be a compressed charge and tolerances could cause dangerous pressures. No such warning at 46 grains, with 3300 FPS velocity, almost exactly half way between 30 Remington and 358 Winchester with a 200 grain bullet! I am thinking I will fireform one case at 40 grains and double check the water volume.
If all checks out I will use 46 as max and look for a load in the 42 to 45 range that is accurate and does not kick too hard. I weighed the completed rifle and right at 9 LBS, 1 pound less than a scoped 1917 Enfield.

Tied the 35/40 to a chair and started with 40.0g Varget, pulled the trigger with a string and went as expected.
Next shot with 43.0 grains, no problems.
Next shot with 46.0 grains, was also uneventful.
I had refigured for a compressed load and got 47.2 grains, so I loaded this as a proof load as Q/L still showed it to be safe. Same results, no signs of pressure. When I checked the powder depth with 47.2 grains, it was still not a compressed load, so the case capacity of the unfired Remington case is greater than I originally figured.
The 47.2G fired case is on the left an unfired case on the right, the shoulder did move at least .010 on the fired case. I will need to refigure after checking water capacity as the fired case will have more volume. (see photo below on optical comparator)
After untying the rifle form the chair I fired one 43 grain round offhand and it was not unpleasant.

Here piggy piggy! (insert smiley here)

---

FredC wrote on Dec 30^th, 2015 at 5:59pm:

Switching to 35/40 it shows 47 grains of Varget to be a compressed charge and tolerances could cause dangerous pressures. No such warning at 46 grains, with 3300 FPS velocity, almost exactly half way between 35 Remington and 358 Winchester with a 200 grain bullet!

Just revisited this post and noticed a typo. the 3300 FPS should have been 2300 FPS. 3300 would be an insane magnum velocity!
Yes that was another typo should have been 35 Remington. The problem with proofing your own material is you see what you actually meant instead of what you typed. Getting old does not help either! Getting old sure beats the alternative which is dying young.

And should it not also be .35 Remington?

Dick,
Thanks,
Fred