2F vs 3F for shot loads

[The Baron]

After watching Mike Beliveau's videos and doing some shooting myself, I've been thinking about 3F vs 2F in my .62 fowler. Mike referenced a heavy load of 100gr. 2F in a 20ga fowler. I've been doing most of my shooting with 70-80 grains of 3F. How do those loads compare, i.e. I would assume it is unwise to work myself up to 100gr. of 3F. Are there any references of velocity output with varying charges of 2F/3F? (thought I read somewhere to reduce a 3F load about 10% from 2F, so maybe 90gr. 3F = 100gr. 2F)?

Also, in terms of patterning shot loads... I wonder if 2F starts the payload off a little slower and might not slam the shot as bad, so maybe tighter patterns? Only one way to find out I guess... and I do own a chronograph... :hmm:

 

[BrownBear]

Dunno about your fowler, but all my smoothies pattern 2f better than 3f. But I've learned they also pattern 1f better than 2f. That's in 20, 12 and 10 gauge. Based on that, I think you're right about the slower start of 2f than 3f helping explain it.

One point worth contemplating: The old guide "more shot less powder" indicates you generally get better patterns when you use a 100-grain powder measure of shot with a 90-grain measure of powder, for example.

My dinking around has shown in my guns it's 1:1 when using 1f, or dispensing the same volume of powder and shot (100-grain measure of powder and 100-grain measure of shot in my previous example). I like that a lot along with the improved patterns, for being able to carry and use only one powder measure for both. Small detail, but a factor in my days afield.

 

[Stumpkiller]

By weight the same volume of 3F weighs about 6% more than 2F.

That is, if you have a 2F calibrated volume measure that throws 100 gr it will hold 106 gr of 3F.

There is also likely a difference in burn rate (although both are VERY fast) so dropping 10% is a good practice.

 

[The Baron]

By weight the same volume of 3F weighs about 6% more than 2F.

That is, if you have a 2F calibrated volume measure that throws 100 gr it will hold 106 gr of 3F.

Thanks! I did not know that.

I wonder if these commercial powder measured (brass adjustable) are calibrated for 3f or 2F... time to throw some 2F/3F charges over the scale and see what I find. Don't have any 2F in house at the moment, but will share results when I do that.

 

[Loyalist Dave]

They aren't calibrated for either, they are calibrated on a unit of volume known as a grain. It's from the avoirdupois and apothecary system of measurement.

So pretty consistent by reducing the charge from 2Fg to 3Fg by 10% gives roughly the same amount of actual powder. But that's very crude because the larger grains burn slower = less muzzle velocity, and if you used a good load from your 20 gauge in your 16 gauge = less pressure generated due to the larger chamber, so also less MV.

100 grains in your 20 gauge = 3.6 drams, which is pretty stout (imho), depending on the amount of shot that you will throw.

LD

 

[hanshi]

The heaviest 3F load I've used in my 20ga is 75 grains with a 330 grain lead ball. I use a lot of 3F in my smoothbore. But I've also done some shooting with 2F and am of a mind that it might be better with shot loads than 3F.

 

[rodwha]

Volume???

My digital scale isn't measuring volume but weight just as projectiles are weighed this way.

If I'm misunderstanding something please explain.

 

[George]

They aren't calibrated for either, they are calibrated on a unit of volume known as a grain. It's from the avoirdupois and apothecary system of measurement.

Are you sure you want to stick with that explanation?

Spence

 

[George]

I wonder if these commercial powder measured (brass adjustable) are calibrated for 3f or 2F...

I have two of those measures, the type with the swinging funnel and the sliding central rod with calibration marks, and each is more inaccurate than the other.

One seems to have been calibrated with 2F, it drops charges at least close to the calibration marks with that, does much worse with 3F.

The other doesn't seem to have been calibrated for either, it drops charges far off the nominal amount with both granulations.

On each the error is cumulative, the larger the charge you drop the more extra, unknown powder you get.

I don't trust either of them, I have re-calibrated both for the two granulations and pasted the table on the measure. This can be dangerous. On one of them the 110 grain mark drops 135 grains of 3F.

Spence

 

[Stumpkiller]

The other doesn't seem to have been calibrated for either, it drops charges far off the nominal amount with both granulations.

On each the error is cumulative, the larger the charge you drop the more extra, unknown powder you get.

I don't trust either of them,

Spence

And that is wise.

I have a measure only marked "ITALY" that has a plunger slide and is marked 50 to 100. At 100 it throws 120 gr FFg and 130 gr FFFg. That's a 30% overload.

I use a powder scale to measure loads. Find the most accurate. THEN make a volume measure that throws that amount. I keep a separate bag and measure (and horn) for all of my muzzleloaders so I know I'm ready when I grab that bag.

 

[nhmoose]

:thumbsup:

 

[Lorne Johnson]

Avoir du pois is a system of weight. 7000 grains to the ounce.

 

[azmntman]

:shocked2: I was thinking it was some type of French possum stew :youcrazy: :rotf:

 

[The Baron]

:shocked2: I was thinking it was some type of French possum stew :youcrazy: :rotf:

Nasty! LOL

 

[BrownBear]

Mmmmm.... Possum....

Now you're talking!

I grew up on the stuff and still have a sweet tooth. :thumbsup:

 

[Loyalist Dave]

Avoir du pois is a system of weight. 7000 grains to the ounce.

Ah BUT it also a used for volume.. For an ounce of what? The substance that is used as the standard is then used to establish volume as well.

Bullets are measured in grains with 7000 grains to the pound, with an ounce of pure lead = 437.5 grains. Yet 100 grains of powder is not equal to 437.5 grains of lead shot in mass, BUT a lot of 100 grain powder measures throw an ounce of shot or in other words about 438 grains of lead.

LD

 

[George]

Avoir du pois is a system of weight. 7000 grains to the ounce.

That's 7000 grains to the pound, 437.5 grains to the ounce.

Spence

 

[George]

Ah BUT it also a used for volume.. For an ounce of what? The substance that is used as the standard is then used to establish volume as well.

Bullets are measured in grains with 7000 grains to the pound, with an ounce of pure lead = 437.5 grains. Yet 100 grains of powder is not equal to 437.5 grains of lead shot in mass, BUT a lot of 100 grain powder measures throw an ounce of shot or in other words about 438 grains of lead.

An ounce of anything...feathers, pinto beans... weighs 437.5 grains. The relationship between the weight of anything and its volume depends on its density. The fact that a 100 grain measure for powder holds about one ounce of lead is purely coincidental.

A grain is a fixed measure of weight. The volume associated with it varies, depending on what you are weighing.

Spence

 

[Lorne Johnson]

The "square load" starts with a measure of an ounce of shot (of undetermined size), and the same measure is used to measure the powder (of some un-named granulation). As a matter of convenience that is often called an "ounce" load of powder in reference to black powder in muzzle loaders. It's not a liquid ounce, and it's not an ounce by weight.

Seems to work for folks on this board though.

 

[George]

My understanding of a square load doesn't involve any specific weights, just equal volumes of powder and shot. Use whatever measuring device you want, use it for both powder and shot, and the load is "square". It's a made-up term, though, so can mean different things to different people. I prefer the term "grains equivalent", meaning a volume of shot equivalent to the volume of powder.

In LD's post above he said a 100 grain powder measure would drop 1 ounce of shot. That's not exactly correct. A 68 grain powder measure will drop 1 ounce of shot, give or take, depending on the granulation of powder and the size of shot.

Spence