Author Topic: Triple Seven Compression (Read 1495 times)

McLernon · « **on:** December 27, 2007, 05:49:00 AM »

I plan to use 777 in my 45-70. I'll have to compress it using the bullet a fair amount. Has anyone used 777. How much can it safely be compressed??

Mc

burntmuch · « **Reply #1 on:** December 27, 2007, 05:51:04 AM »

How much t7 are gonna use?

quickdtoo · « **Reply #2 on:** December 27, 2007, 05:55:47 AM »

Hodgdon data shows 60gr by volume powder measure.

Tim

http://www.hodgdon.com/data/muzzleloading/granular/t7cartridge.php

McLernon · « **Reply #3 on:** December 27, 2007, 06:00:40 AM »

I plan to use 43 gr by weight with a 500 gr LCGC bullet that I bought locally.

Mc

McLernon · « **Reply #4 on:** December 27, 2007, 06:05:11 AM »

This whole thing of 'by weight ' or 'by volume' is confusing. There is no way I could get 60 gr by weight into the case and still insert a 500 gr bullet on top of it. Even 43 gr gets compressed enough to worry me. And I get 1200 fps. Confusing, no?

Mc

coyotejoe · « **Reply #5 on:** December 27, 2007, 06:29:38 AM »

Black powder is wonderful stuff!

You can increase the load, reduce the load, compress the load and you always get predictable results. None of that holds true with smokeless powders and the black powder substitutes often seem to behave more like smokeless powders in some instances. With triple seven we are told it should not be compressed and I have seen very eratic results with extreme variations in velocity and pressure when it is compressed. If you can possibly get real Goex black powder that is by far the best choice in all applications. I have loaded quite a few black powder cartridges with Pyrodex RS with good accuracy, often beter than black but triple seven is one I would avoid for any use whatever. If you absolutely MUST use that witch's brew, I'd suggest you measure to the base of a seated bullet and fill the case just to that point so that there is no compression and whatever amount that happens to be is the maximum amount you can use and whatever velocity that produces is the velocity you have to work with. In that respect it is no different than with black, except that you load the black powder 1/16" higher than the bullet base so that the powder is compressed by 1/16 inch.

fanner50 · « **Reply #6 on:** December 27, 2007, 06:31:13 AM »

Weight and Volume are just two different ways to measure things. Use one or the other but they have to correspond. I load Jim Shockey Gold in my 45-120. I fill the case to allow about 1/16" of compression as recommended by APP. I set my powder thrower up to do this with two strokes because it doesn't hold enough to do it in one yours should in the 45-70. I've never weighed the load. It isn't necessary as the volume is correct. Different powders weigh differently (does that make sense?) because of their chemical make up and granulation etc. I would recommend that you figure out where the 500 gr bullet seats (if your rifle has the standard short throat it will need to seat deeper) and fill up to that point with very little compression and adjust from there.I believe the original military 500 gr load for the 45-70 only had 50 gr of FFG by volume. I'm sure someone will correct me if I'm wrong. You need to crono your loads also taking manuals as the gospel will cause problems remember they are a guide to go by. Good luck BPCR is great fun to shoot. JMHO - F50

McLernon · « **Reply #7 on:** December 27, 2007, 06:41:20 AM »

Thanks for the tips guys and have a Happy New Year!!

Mc

quickdtoo · « **Reply #8 on:** December 27, 2007, 06:46:39 AM »

Give em books and all they do is eat the covers!!

Here's Hodgdon's recommended cartridge loading procedure.

Tim

Cartridges: Use data specifically developed for Triple Seven FFG only. Cartridge loads should be used exactly as listed in this brochure. You may safely use a card or polyethylene wad up to .030" in thickness to protect the base of the bullet. Loading density should be 100% with light compression not to exceed .100". Testing has shown that Triple Seven will perform best when the bullet just touches the powder. Allow no airspace between the base of the bullet and the powder. Do NOT reduce loads by means of filler wads of inert filler material such as Grits, Dacron or Grex. Do not heavily compress powder charges. The use of filler wads, inert fillers or heavy compression may cause a dangerous situation which could cause injury and/or death to the shooter, bystanders or damage property. Do not create loads for cartridges not listed. Contact Hodgdon Powder Company for recommendations concerning other loads. *See WARNING below

http://www.hodgdon.com/tripleseven/loadnote.php

McLernon · « **Reply #9 on:** December 27, 2007, 06:55:51 AM »

Tim:

I wrote the post because some of the guys in the rifle club I am a member of compress the ' bejeebers' out of the t7 and so I wondered what the rest of the world is doing with it. With regard to eating the covers, I like the light cardboard covers best, they don't get stuck in my teeth!

Mc

Busta · « **Reply #10 on:** December 27, 2007, 07:00:55 AM »

Quote from: McLernon on December 27, 2007, 06:05:11 AM

This whole thing of 'by weight ' or 'by volume' is confusing. There is no way I could get 60 gr by weight into the case and still insert a 500 gr bullet on top of it. Even 43 gr gets compressed enough to worry me. And I get 1200 fps. Confusing, no?

Mc

MC,

Why 777? Not that I am knocking 777, I use it all the time in my muzzleloaders. If you are using 43 grains by WEIGHT, that would approximate to 55.34 grains by VOLUME.

In my experience 100 grains by VOLUME of 777 FFG averages around 77.7 grains by WEIGHT (might be where the name came from?). This may vary a slight amount depending on humidity and storage practices. The best way to determine what your conversion rate is is to get a Black Powder VOLUME measure and throw 10 VOLUMETRIC charges weighing each one separately, then take your average for you LOT of powder.

A 60 grain by VOLUME charge of 777 FFG will weigh approximately 46.62 grains by WEIGHT with my LOT of powder.

If you are using 777 FFFG, the conversion will be different, only you can determine what your LOT of powder will be exactly.

In my muzzleloaders, I firmly seat the bullet on the powder, but that is different than seating a bullet in a crimped case. I would call Hodgdon and ask them about compressing their powder.

Liike Quick pointed out already, that data is by VOLUME powder measure. VOLUME measurement is still the standard for Black Powder and Black Powder Substitutes.

To make things even more confusing 777 FFG should be reduced by 15%, as compared to Black Powder and the other Substitutes for equal velocities. 85 grains of 777 FFG by VOLUME is the equivalent to 100 grains by VOLUME of Black Powder or Pyrodex RS.

Hope you aren't more confused than you were before this post, but if you are don't be afraid to ask for clarification. Safety First!

McLernon · « **Reply #11 on:** December 27, 2007, 07:19:56 AM »

Thanks Busta:

I take it that 60 gr of t7 or BP is measured with an instrument that is marked off in gr's(weight) but is actually a volume of powder. When you dole out 60 gr of powder with the volume measuring instrument it actually weighs on a scale 46.62 gr's, right?

Mc

Busta · « **Reply #12 on:** December 27, 2007, 08:19:43 AM »

Quote from: McLernon on December 27, 2007, 07:19:56 AM

Thanks Busta:

I take it that 60 gr of t7 or BP is measured with an instrument that is marked off in gr's(weight) but is actually a volume of powder. When you dole out 60 gr of powder with the volume measuring instrument it actually weighs on a scale 46.62 gr's, right?

Mc

Mc,

The Powder Measure is set up for real Black Powder and goes back to what was a STANDARD measurement for the weight of Black Powder. The funny (well maybe not so funny) thing is that 100 grains by VOLUME of Black Powder is supposed to actually WEIGH 100 grains by WEIGHT. 100 grains by VOLUME of some Black Powders actually WEIGH in the 105 grain by weight range. So it is not an exact science with the powders made today, especially the Black Powder Substitutes.

Most of the BP Subs actually WEIGH much less than the VOLUME measure indicates. They are made to approximate the same types of velocities as Holy Black by VOLUME measurement. The exception to that rule is 777 loose powder, it is much more potent as described earlier, and needs to be reduced by 15% for equivalent velocities.

There are conversion charts that have been published, but I find they vary a bit, probably due to the humidity and storage practices. When I throw a VOLUME charge, I overfill the VOLUME measure and then tap the side to settle the powder then scrape level at the top. I always tap the exact same # of times for consistency. If I really want to shoot for groups, I WEIGH the powder out using my conversion and store it in plastic vials before shooting.

Only you can determine what your 60 grains by VOLUME of 777 actually WEIGHS exactly, but that should be in the Ballpark.

All my weights may be on the high side, since they are all tapped and settled. If you were to just fill and pour, your results will be lighter. I have seen charts range from 74 to 78 grains by WEIGHT of 777 FFG being equal to 100 grains by VOLUME. So weigh some volume measurements of your powder to find out what your Lot # actually weighs.

To make matters worse, not all BP volume measures are calibrated to throw the same exact charges as indicated. There are several types of brass ones and plastic ones. They vary as much as +/- 5 grains by volume on a 100 grain Volume charge in my experience, so throw that into the equation too.

McLernon · « **Reply #13 on:** December 27, 2007, 09:14:05 AM »

Gotcha Busta, thanks again.

Mc

quickdtoo · « **Reply #14 on:** December 27, 2007, 09:38:23 AM »

Be safe Mc, we need ya here with all fingers and eyes!!

Tim

walkingwolf · « **Reply #15 on:** December 27, 2007, 05:22:00 PM »

I use 58.5 gr. 3f a 535 gr. lead and a nitro card. compressed with a compression die. so far it shoots well at 750 yrds.

chrsm · « **Reply #16 on:** December 27, 2007, 09:24:15 PM »

I do not like 777. To me it is not consistant, I have tried it in my 450m handi and smokepole. I could feel the differance from shot to shot in both. Did not like it at all. For me black is the only way to go for this kind of shooting.

coyotejoe · « **Reply #17 on:** December 28, 2007, 06:57:02 AM »

We're all making this more complicated than it needs to me. You just set up your powder measure so that it fills the case to the base of the bullet with no air space and with very little compression. That is the load and it doesn't mater what it weighs not what it measures by volume, that is the load and you can't change it by more than a grain or two. If you then want to record that weight for furure reference that is fine but it is the case and bullet seating depth that actually determine the powder charge, not some arbitrary number out of some book.

McLernon · « **Reply #18 on:** January 11, 2008, 01:49:37 PM »

There are those that argue that adequate powder compression is required in order to get the cleanest and most complete burn possible so that the number of shots between cleanings is maximized. This I understand is standard practice among BP specialists, even going to the extreme of multiple compressions employing a press.

/

Mc

Smokin Joe · « **Reply #19 on:** January 11, 2008, 02:57:38 PM »

Mc, these are the BPCR guys that either blow or wipe between shots, drop thru a 36" tube, hold the case against a vibro case cleaner, index the cases by filing a notch on the rim and then swing a voodoo doll made from rawhide and bear guts over their head before taking up the trigger slack.
Some compress, some don't. I'd say just load to the bullet base and pull the trigger. 90% of the time, it ain't the arrow...............it's the Indian.

McLernon · « **Reply #20 on:** January 13, 2008, 08:10:02 AM »

Hi Smoke'

That's me you just described, except for the voodoo doll. They never worked for me

Mc

Cottonwood · « **Reply #21 on:** January 14, 2008, 01:26:23 AM »

Quote from: fanner50 on December 27, 2007, 06:31:13 AM

I believe the original military 500 gr load for the 45-70 only had 50 gr of FFG by volume. I'm sure someone will correct me if I'm wrong.

Fanner50 - The old US Calvary loads for the carbines were 50.0 gr of FFg for the 45-70 Springfield Cadet rifles with the 22" barrels but the standard rifle load was 70.0 gr of FFg under a 500-gr bullet.

As far as compression goes, DO NOT USE A HEAVY COMPRESSION.

Several years ago, I posted my results from doing such, and it yielded stuck cases with obvious signs of over pressure to the cases, with bulges close to the head stamp/rim end result was that I could not re-use the cases.

From Triple 7 Fact: Because it is a high energy propellant, we recommend very light compression of the powder rather than the heavy compression used with other powders. Hodgdon Powder Company provides specific data for cartridges using Triple Seven.[/b] so please be careful in using compression with Triple 7.

http://www.hodgdon.com/tripleseven/tripleseven-faq.php#used%20in%20cartridges

For the best possible load with your 500-gr bullets, find where your seating depth is, then measure your distance that will be from the base of the bullet to the primer hole in the case. You want to then use a set of calipers to measure that distance to find your powder depth. Only put enough in to seat your bullet comfortably over the powder charge. Then find your appropriate card wad that will be seated between your bullet and powder. The card wad will give you the added minor compression that you will need and only use. Do not push the limit with Triple 7.

Have fun and stay safe.