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Triple seven in my Lyman GPR?

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N.Y. Yankee

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Recently, I was out with the GPR to test the reliability of 777 loads in the .54, mainly, for hangfires. The gun fires when it should but I did notice a lot harder recoil than I had remembered with FFg Goex, but it had been a little while since I had fired her. Later, I found the shots were hitting higher than I remembered with FFg. Still, not putting 2 and 2 together, I continued to fire about 24 shots at distances of 50, 75, and 100 yards, getting a couple of hangfires and consistently high impacts. Resolving to install a new front sight, I returned home to give her a good cleaning.

From then until just now, I had never seen any information on the power of 777 and loading recommendations. I had just loaded the 777 the same as FFg. It's a "black powder substitute" after all, right? Well, just now, I find out that you are supposed to reduce 777 loads 15 Percent! from Goex loads, because of 777's higher pressures. Now the light comes on and the higher recoil and much higher impacts makes sense! The max load for my 20 yr old GPR is supposed to be 100 gr (FFg?) So, am I loading the equivalent of 115gr 777? Am I going to blow up my gun? Am I in danger? The gun is in excellent condition and seems fine. It does not spit caps nor lock back on half cock when fired. I have not noticed any anomalies in the barrel or bore. So what can you tell me about this? I dont mind re-sighting the gun if the payoff is higher velocity with the .530 patched round ball, but not at the price of a blow up.

What do you know about the max charges for the .54 GPR? For now. I will revert to FFg in this gun.
 
Have tried to simplify my life. Shoot fff Swiss in most everything and virtually eliminated using the wrong powder. Still have a few containers of Pyrodox from the 1980s or 1990s I believe, and my first and last container of 777. It is dated 2001. and I t’s about half full with a couple of those descant packs in it to suck up any moisture. Keep the few sub containers around just because.

Many have success and love the various subs. Can’t argue with success. 100 grains of 777 didn’t harm your barrel. If you must, find the 777 load that gives you the best accuracy and hopefully it matches your ff Goex point of aim. It will be less than 100 grains by volume. Or just go back to your proven Goex load of 100 grains.
 
But that Lyman manual was written before 777 powder was in existence.

The Lyman rifle won't blow up if you load 100 grains of 777. There is no advantage in exceeding the Lyman manual's restriction of 100 grains of black powder. It is up to you to adjust the powder charge to match the limits set in the manual. Similar adjustments would be made when substituting 3fg GOEX for 2fg GOEX.

You will be better served in hunting success by using the most accurate load that meets your hunting requirements.

Yes, you may have gained some range as evidenced by the higher trajectory, but at what expense? You have more felt recoil. What happened to your group size? The groups probably opened up. There will be more wear and tear on your rifle. Back down on the powder charge to the equivalent performance of the 100 grain black powder defined as the maximum specified in the Lyman manual.
 
777 is tricky. Velocity is usually lower then BP. That lets the barrel rise more before the ball exits to hit high. It does NOT like any compression so it must just be touched by the ball or bullet. In BP cartridges you usually can't get enough in to equal BP.
I will give you all a hint for Pyrodex, good stuff but it breaks in shipment. I use a mesh cloth over a box frame to screen a new jug. I was getting poor results as the jug got lower to find fines of powder near the bottom. I get a large pile of fines that I burn up. Accuracy has increased a bunch. Pyrodex needs a little compression so I made a spring loaded tool to seat by putting it on the ramrod once the ball is down to get the same pressure each time. I push to bottom the spring. Works with real BP too. My friend throws his rod down and I told him some day the gun will fire from whacking the powder. Even smokeless can go off if struck.
Several things cause higher impacts, A heavier bullet or a slower one. It is when the projectile leaves the muzzle in recoil. What you feel at your shoulder says nothing. Putting more powder to add to bullet weight has the same affect and all the powder will not burn before the end of the barrel. Adjust so all powder is consumed at 3" from the muzzle.
We tried more once to have flares shoot out and burn in the grass. Velocity went down big time.
 
N.Y. Yankee
The other members pretty much covered the loads for 777 but if you are shooting it under a patched ball, you might want to check the patches after they have been shot.
777 has a reputation for burning patches and if your patch gets burned while it is being shot the accuracy will go down the tubes.

One solution to the burned patch situation is to reduce the powder load. Another is to load a small amount of corn meal or Cream of Wheat on top of the powder load before loading the patched ball. That barrier will protect the patch from the high temperatures 777 develops.
 
777 is measured in volume not weight. They recommend that you reduce the load by 15% when you load. 100 grains of black powder use 85 of 777. Information directly from manufacturers web page.
 
I must also be taken to task for failing that these black powder substitute powders are only to be measured by volume, not weight. I am so totally accustomed to measuring by volume that I forgot the caveat about measuring by weight.100 grains of actual weight of triple 7 is a serious overload. 100 grains volume of triple 7 is an overload of 15%.
 
I must also be taken to task for failing that these black powder substitute powders are only to be measured by volume, not weight. I am so totally accustomed to measuring by volume that I forgot the caveat about measuring by weight.100 grains of actual weight of triple 7 is a serious overload. 100 grains volume of triple 7 is an overload of 15%.

5 out of 4 people are terrible at math.
 
Don't overthink it, back before I knew better I used to just fill the chambers on my Uberti cap and ballers with 777 or Pyrodex , or just measure out 60 gr and pour it into my Buffalo Hunter. 58 and it worked, so whatever.

Do you really think Jim Bob and Earl are out there zeroing a CVA Hawken for deer season, doing maths? :) they're buying a can of 777 RS at Wal-Merts and dumping whatever fills up a 12 gauge hull down the pipe and stuffing a moldy white patched round ball down to see if it hits close to the sights. They may attempt to clean it afterwards. They're gonna be fine .
 
buying a can of 777 RS at Wal-Merts and dumping whatever fills up a 12 gauge hull down the pipe and stuffing a moldy white patched round ball down to see if it hits close to the sights. They may attempt to clean it afterwards. They're gonna be fine .
Shouldn’t post manure like this. Using a 12 gauge hull for a powder measure they are likely NOT ‘gonna be fine’. An empty 12 gauge hull holds well over 200 grains of black powder.
 
It's one of those "funny not funny" things because I saw two guys fitting the aforementioned description doing this a few years back. I didn't ask them if they topped it off, if it was a 20 gauge , or if they just filled it 3/4. They were using a Dixie cup as a "flask".

If they're still alive and I see them again I'll warn them , they were pretty old then
 
These people do exist , sorry to say. Just trying to add some realistic flavor that people who dont hyper analyze every grain of powder or weigh bullets exist in the wild and usually they manage to avoid injury. Well, I guess I'll just pretend they don't exist here in online forum fantasy land.
 
I'm sure most of our members and I realize your statement about the 12 guage shell was made tongue in cheek but we do get a lot of people on the forum who really don't know anything about black powder loads.
When some of these people see a post that makes something dangerous sound like it is OK to do, they might try doing it. :eek:

Yah. I know. It takes some of the fun out of posting. :(

We really need a good rolling on the floor laughing smiley on the forum. IMO this stupid grin doesn't cut it. :D
 
Well, it was kinda tongue in cheek but these guys were utilizing what appeared to be a shotgun hull , I guess (disclaimer: Never do this)
 
Well, it was kinda tongue in cheek but these guys were utilizing what appeared to be a shotgun hull , I guess (disclaimer: Never do this)
At times I am a sarcastic SOB. My bride and dear old mom can confirm this. I appreciate and enjoy a snappy smart ass response/post as much as anyone. But don’t say obviously stupid and dangerous stuff is just fine and peachy. People look at this site as a collection of experts (yours truly not in that club) and a subject matter reference. Point of my initial response, and what I believe Zonie is saying, some fool out there is going to take you at your word because they read it on the internet, and try it. My quick volume calculation says that a 12 gauge hull will hold more than 230 grains of black powder. A load safe in very few firearms.
 
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