This has probably been answered many times, but I’m confused and think that some of the experts may be able to help. Here’s the facts;

1. A 7mm rem mag has a COAL of 3.290.

2. With a 168 Berger and H1000, the fill ratio is 100%

3. Assume that the magazine allows a COAL of 3.420, am I ok to load the case to 100% with H1000?

I guess the basic question is, if your magazine allows a longer COAL than SAAMI, how do you know how much additional powder one can add?

This is about as basic as "how long is a piece of string".

Firstly, is there room in the throat to load the bullet that long? Changing from a 0.02" jump to 0.01" into the lands will have a significant impact on pressures.
Secondly, is the existing load showing any signs of pressure?
Thirdly, how does the existing load's velocity compare with other powders in the same rifle and with all other components the same?

If there is enough lead, and if the velocity is somewhat lower than you have been able to achieve with other powders, and if the existing load is showing no signs of excess pressure, then I think you should be OK.

But to be safe, load it out, back off 2 grains and work up from there.

Thanks for reply. This is not a factory rifle and is Long-throated.

As I see it in simplified terms, with a Long-throat and longer magazine, i really have a potentially different cartridge. I guess that I need to figure out how much powder increase these two elements provide and maybe look to the loading recommendations for analogous and larger capacity 7mm’s

Max powder in loading manual(s).

Forget maximum charge in manuals.

It is a custom gun.

If the new length will chamber, use normal loading procedure to see how much powder you can load.

We only use loading manuals as a guide, and do not follow them.

All one has to do is look at different manuals and you will see what I mean.

What S said; load data varies all over the place since no two rifles are the same and yours is definitely outside the curve.
Only one way to develop loads and that is to develop the load for your rifle, basing a "max". load on the well known signals we bandleaders use. Not too scientific.
So, while it might be ok to randomly stuff the case full of a very slow burning powder, do not do it. Work up to it.
Why do you need that extra 25 fps anyway? Is a question I alway ask.

In practice, the answer to question #3 is NO, pressure would definitely be higher loading the longer COAL to 100%. Now if the 3.29" load was considerably below max pressure, then you might be able to load the longer COAL to 100%, but the pressure would still be higher.

Not necessarily because you have created a much larger combustion chamber, thereby allowing more powder to be burned at the same pressure level. In theory, and usually in practice. It then becomes a different cartridge. However, still don't do it without working up to it, just to make sure. But in reality, with the very slow powers, it usually does not make any difference. No hard and fast rules...

quote:

Originally posted by Saeed:
Forget maximum charge in manuals.

It is a custom gun.

If the new length will chamber, use normal loading procedure to see how much powder you can load.

We only use loading manuals as a guide, and do not follow them.

All one has to do is look at different manuals and you will see what I mean.

+1

I’m not sure why folks treat reloading manuals as if they give much more than a starting point. Look at 5 different manuals, and you’ll get 5 different starting points, and 5 different max loads. That should tell you something. You’re on the right track now dinger. Custom rifles have custom chambers and throats, and can be very different from factory offerings. You may be surprised how much H1000 you can run with. Keep in mind also, that the more concentric the work on the rifle, the more pressure it will take before brass gets tight on extraction. Another advantage of the well built custom rifle.

The way I’d deal with it is use 5% under max as the starting point with that powder and length, and then run a ladder test up until you hit either a node, a velocity target, or traditional pressure signs.

You effectively have a larger cased cartridge here, so I’m guessing by about 5% give or take. Honestly, if it isn’t overbore, H1000 is pretty slow, and I doubt you an get enough in to really get yourself in trouble, but safe practices need to be followed…

I suspect you will end up 5 grains or so over book max, but let your rifle and chronograph tell you what it is.

you have to figure out how much more case capacity you gave yourself by moving the bullet out beyond what the book [oal] says.

if you gain a whopping 2% [shrug] then that's how much more you can use.


it's like loading a wild cat or Ackley case with no data.
all you can work from without pressure equipment is a known same case/bore capacity.

I ran your scenario through Gordon's Reloading Tool and came up with the following numbers:

Berger 168 with 100% fill of H1000 at 3.29" (67.0 g) gives 2841 fps @ 52.2 kpsi
Berger 168 with 100% fill of H1000 at 3.43" (69.1 g) gives 2884 fps @ 54.4 kpsi

In this case, because the powder is slow enough that a 100% fill gives way below the max pressure allowable, it would be safe to do and gain you about 40 fps. To load the longer COAL to the same 52.2 kpsi would take 68.3 g, or about 62% of the additional case volume.

Software only gives you an indication of what MIGHT happen.

Nothing else.

We tried a test.

To blow up 3 rifles.

On purpose.

First thing was to find 3 different calibers with roughly the same case capacity.

And then find the rifles to suit them.

Fastest powder we had was Hodgdon HP38.

A wooden frame was built, put in our underground tunnel 50 yards in.

A fishing line was bought to tie to the trigger to fire the rifles.

3 separate Gopro cameras were set at different angles.

Loading software gave us an indication of pressure we might get.

Something really ridiculous.

Over 200,000 psi.

The cartridges we found were a 243 Winchester, a 308 Winchester and a 303 British.

Rifles were a Parker Hail 243
A Brno 505 308
An Enfield 303.

Cases were full, I cannot remember the exact amount, but all were the same.

The 243 Parker Hail fell to pieces.

A proper blow up.

If it was shot the shooter would have sustained very serious injuries.

The Brno 308 faired a lot better.

The stock cracked by the magazine.

The bolt could be opened with a hammer.

No serious damage.

In fact, being a bunch of nuts with a slight lack of that grey matter normally found between the ears.

We took the barrel off.

Wait for it!

We chambered for the 300 Winchester Magnum.

We opened the bolt face to suit.

I know.

We should have been admitted to a mental asylum years ago.

We did not.

So we are carrying on.

Fill the case with HP 38, and fired it.

A bit more damage, the action held together.

The 303 Enfield suffered the least.

We put the pieces of the Parker Hail on a wooden board, it is on display in our shooting room.

I get funny looks when or see it, and ask who shot it.

The look of utter amazement, and disbelief, on their faces has to be seen to be believed!

Every now and then some would ask if we had ever had a rifle blow up.

The argument stops when I tell them yes, on purpose!

One point that’s seems clear is a lot of screwing around for marginal gain that will make zero difference in the real world.

I’ve always been spooked a little by the thought of excessive pressure ever since a hunting trip for Coues Deer in old Mexico.

I had a Melvin Forbes Ultralight in 257 AI. A great shooter, I had it loaded to near maximum. I was rushed with work, etc., and loaded ammo the night before leaving. Somehow, the die go changed and I loaded them long. Dumb, but I didn’t measure them.

When I got to Mexico, the first morning of the hunt, when I loaded the magazine, I noticed that I could barely get them in the magazine. Wtf? I tried to chamber and it wouldn’t go in until I banged hard with the heal of my hand. There were no extra rifles in camp so decided that I was going to hunt anyway. The first morning my guide and I located a nice buck and managed to get within 150 yards. I got in the prone position and when I pulled the trigger there was one hell of a bang. Worse, I hit the buck in a front knee and the bottom half his leg was dangling; two feet off from where I was aiming. I went to eject the spent case and reload, but couldn’t open the bolt. I reached over and grabbed a rock and with quite a bit of pounding was able to open the bolt. Now, I got a real problem, an injured deer that rather than run was kinda hobbling around in a circle and what was an unsafe gun. I had no choice but to try and shoot the deer. I adjusted for two feet off and somehow managed to kill the deer on the next shot. I don’t even remember where the bullet hit but the ballistic tip did the job. If there is any humor in the story it is when I saw the buck collapse, I turned to look back at my guide who was American and a avid shooter and Hunter, and saw that he had moved back 20 feet from me.

Reloading books are a starting point and very helpful, IF you know how to interpet them, just remember to start at beginning loads and work up a grain at time, if your new to the game.. My advise will stop here, the rest comes with time and effort and gainful knowledge.

Ray, certainly good advice, but the difficulty with that is that I understand many of the pressure signs that we use are far from accurate. I have a chronograph. How do I know what the velocity will be with the increased capacity? I guess that I could measure the amount of increased powder, calculate the percentage increase and take 25% of the increase.

For example:

1. A cartridge case under SAAMI guidelines takes a 100 grains and has a velocity of 3000 fps;

2. Add 10 grains and you have a 10% increase;

4. 10% of 3000 fps is 300 fps;

5. Velocity should increase .25% of the 10% increase;

6. 2.5% of 300 fps is 75 fps, for an anticipated velocity of 3075.

I stand corrected. Seems I've spent a lifetime trying to shoot well while not blowing myself up. An old, conservative, maybe obsolete practice admittedly, but I remain intact. Still wondering about pressure, safety, and what a few FPS really means in the real hunting world.

depends on what your trying to make the bullet do when it gets there.

quote:

Originally posted by Lamar:
depends on what your trying to make the bullet do when it gets there.

That is the biggest question!

I am amazed at the vast difference one sees in bullet performance on game animals.

One shoots an impala in the chest.

The bullet penetrates to his rear end and stops.

You shoot a buffalo in the back end.

The bullets penetrates to the neck!

Yiu shoot a lion in the neck the bullet penetrates to his balls??

Same bullet.

Same charge.

These animals are different in size.

Kind of a round about way to answer your question:

I determine what my throat will handle with the bullet I'm planning on using. For hunting, I like about 20 thousandths off as a good starting point.

Then determine if they will still fit the magazine. If the above is all good, I figure out what max is for my rifle by loading 10-12 rounds starting at minimum and increase by .5 grains of powder. At the first sign of a stiff bolt-lift, STOP. back off a full grain from there and this is YOUR max charge for YOUR rifle and components used. (others might look at the primer to see how flattened they are and others measure the expansion on the virgin case just above the web but this never was the best for me). I usually shoot all 10 at the same target and note which ones seem to group even though differing powder weights. This gives you an indication of an "accuracy node".

Return home and load 10 or so of the MAX FOR YOUR RIFLE and return to the range and test accuracy.

If you're trying to maximize accuracy, tweak your powder charge up or down a bit from there and perhaps seating depth in of out by 5-10 thousandths (I know Saeed has said seating depth is a moot point but....)

STOP when you're seeing acceptable results for you! Some rifles are easier to "tune" and others take some load work.

TMI, for free
Zeke