Comparison of Goex 2F and 3F Velocities in a .54 Hawken

[paulvallandigham]

I don't think you would cut your velocity, but the degree of accuracy shooting a PRB might be affected. You might have to use either a smaller powder charge, or be much more precise in how you throw that powder charge to get the same size groups at a given velocity.

I have a .50 cal. rifle that I ordered a GM barrel with a 1:72 ROT. I was delivered a barrel with a 1"48 ROT. The reason I wanted the slower ROT was so this thin, RB only barrel would be more forgiving of any measuring error I might make in the field, using a fixed powder measure. I have now tried both a fixed measure, and my adjustable measure, and have resigned myself to using my adjustable measure because I can throw more consistent powder charges with it than with my fixed measure. That has been the only downside of having what I consider the wrong ROT for this rifle.

 

[longcruise]

Anyone know would the faster twist cut down my velocity rather than 1-60?

I sure don't "know" the answer to that but suspect that differences would be hard to measure. Once you compare two different barrels you introduce more variables than the one (twist) that you are trying to test.

 

[roundball]

Curious what would happen with a 1-48 twist?I shoot prb and 90gr 2f in my 54.Anyone know would the faster twist cut down my velocity rather than 1-60?

Interestingly, all else equal, velocity in the 1:48" may well be higher...the more resistance cause by things like rifling (in your example faster rifling) the higher the velocity due to the increased pressure build up due to the resistance that has to be overcome by the projectile.

For example, it has long been said that among two identical barrels, one rifled, one smoothbore, the rifled bore would actually deliver a higher velocity.

Well, this past summer I had the good fortune to have two Identical GM .62cal Flint smoothbore barrels. I had Ed Rayl add .012" x 1:72" rifling to one of them...then remembering these kinds of discussions I chronographed them...velocity was higher in the rifled bore.

 

[doulos]

Ive really enjoyed this thread. I have a question. Who here besides Roundball uses FFFg in their .58's?
I know this sounds foolish but a long time ago I read an article about FFFg being detrimental to calibers above .54 by actually over time eroding the bottom area of a barrel where the charge sits. Never knew if it was true and I've always used FFg anyways.. Any body ever hear this? What accuracy results are you guys getting in 58 cals with FFg? If its as good as FFg I'll likely get some.

 

[paulvallandigham]

I have friends who shoot FFFg powder in their .62 caliber guns. And at least one shoots FFFg powder in his 12 gauge shotgun. Each gun is a creature to itself, and there will always be exceptions to any " rule of thumb" about black powder components.

The caution about using FFFg powder in larger bore guns is based on the weight of the projectile, and the much smaller comparative diameter of the barrel to the bore in these large guns. It was feared that the higher pressures generated by FFFg, combined with the heavier projectiles, would put undue stress on the guns, and they would fail at some point, injuring or killing the shooter and bystanders.

When barrels were made of iron, it was important to keep pressures as low as possible. That is not a concern today with modern steel barrels, even in the fairly soft steel barrels marketed now.

Perhaps the more important contribution to safety of BL shooters are the steel Tangs and Breechplugs now used in these replica guns.

 

[roundball]

Ive really enjoyed this thread. I have a question. Who here besides Roundball uses FFFg in their .58's?
I know this sounds foolish but a long time ago I read an article about FFFg being detrimental to calibers above .54 by actually over time eroding the bottom area of a barrel where the charge sits. Never knew if it was true and I've always used FFg anyways.. Any body ever hear this? What accuracy results are you guys getting in 58 cals with FFg? If its as good as FFg I'll likely get some.

I think there are a lot of old tales that follow this hobby through generation after generation with no scientific basis in fact...and...no anecdotal evidence of a problem.

Throat erosion in modern centerfire rifles like a .264 Winchester Magnum with max powder charges is known and documented, with notable accuracy fall off as a result.
But I think its safe to say that Goex 3F is nowhere close to being in the same league, and particularly when the dicsussion we're having is simply about the "difference" between 2F and 3F.

Remember, with the modern smaller physical sized bore hot magnum CF loads we're talking about enormous gas cutting potential from pressures in the 50,000-60,000 PSI range. By contrast, our large bore muzzleloaders operate way down low in the 7,000-10,000 PSI range...AND...when 3F charges are used in place of 2F, the quantiy is reduced to keep pressures in the same ballpark as 2F would be operating.

Blackpowder is blackpowder...2F and 3F come out of the same run of powder at the plant at the same time...its just different size granulations. Subsequently there are slightly different burn rates, hence the quantity reductions so the performance characteristics remain similar, POI remains similar, etc. I've used 600-700 large Goex 3F charges in my .58cal, and a few hundred in a .62cal...reduced 10-15% from the posted 2F load data...works perfectly.

 

[BrownBear]

Ive really enjoyed this thread. I have a question. Who here besides Roundball uses FFFg in their .58's?
I know this sounds foolish but a long time ago I read an article about FFFg being detrimental to calibers above .54 by actually over time eroding the bottom area of a barrel where the charge sits. Never knew if it was true and I've always used FFg anyways.. Any body ever hear this? What accuracy results are you guys getting in 58 cals with FFg? If its as good as FFg I'll likely get some.

I had heard all that stuff about 2f being better in58 cal when I was getting in my last shipment of powder, so with two new 58's waiting to be shot, I got 10 pounds of 2f. Wish I had listened closer to my own firsthand experience with 54 and 3f versus 2f. There just weren't enough advantages of 2f in 54 to make me stock it in addition to the 3f I was using in my other calibers.

Turns out same is true for both my 58's. There just doesn't seem to be enough difference in accuracy potential in either of them to make it wortwhile to have the 2f. And meanwhile I can shoot 10-15% less powder using 3f.

As for accuracy with one versus the other, maybe I'm lucky because my rifles like them both.

And the eroding stuff? Never heard of it from a credible source. Lots of INcredible information on the web, and I'll add that to the list. Lots more to be said for doing than for reading.

 

[Herb]

I built a .58 fullstock flint Hawken with a Green River barrel. Used .562 cast balls and .018 pillow ticking patches. First shots were five of 60 grains Goex 3F, average velocity 1333 fps, spread of 30 fps. Next five same, 1315 and 28 fps. Then 80 grains Goex 3F, five for 1497, 41 spread. Then 80 grains Goex 2F, five for 1389 and 51 spread. That's all the 3F I shot in a .58, but this gives relative velocity for these charges.

 

[pchwcf50110]

i use FFFG in all my roundball rifles. it works perfect in my .58, .62, .66, and .72. i use FFG in my .451 and .50 bullet rifles.

 

[Glenfilthie]

I have just started experimenting with 3F in my .54. My old target load was 60 gr. of 2f, so I tried 60 gr. of 3F and my groups closed right up. I will have to try the test again to make sure it isn't a fluke but my big .54 seems to like the fine grind.

Fouling seems to be marginally less with the 3F too, but maybe that is my imagination.

 

[tjohnson56]

When I get up to hunting loads like 90 gr, my .54 likes 2f and there is no doubt about that. Maybe at lighter target loads 3f might work but when I move up to heavy loads it for sure wants 2f.

Now here is the funny part, I shot maybe 300 or 400 rounds out of this gun 2f and 3f and all of a sudden it just took a liking to 2f. Up until then they were about the same, maybe in the future it will waffle back and forth but right now it wants 2f.

Who knows maybe a different patch or lube and 3f and it will shoot as good as 2f but I think you need to keep trying different things even after you think you have the gun broke in. I would have never thought it would take that many rounds for a gun to take a liking to a powder.

 

[paulvallandigham]

YOu need to chronograph both loads to see what the velocity is on the "better" load. Then, when you change lots of powder, or patch lube, check that new load to see if its the same velocity, higher or lower. Any change in components, including patch thickness, and even percussion caps, can change the velocity. That in turn affects the barrel harmonics, and can open up a group.

 

[tjohnson56]

Paul, now we have had several conversations on this forum and you just are not going to rest till I bite the bullet and buy a chronograph are you? :rotf:

You just might be right and I've been thinking about it. Maybe I need to start a thread on witch chrono is a good buy for the dollar and still is a good machine. Can I do that on this forum, it's not PC?

 

[paulvallandigham]

I assure you my suggestion is not personal. I didn't have a chronograph until about 10 years ago.

I bought a Chrony from Sportsman's Guide, because the price was so affordable. My brother has a Competition Electronics chronograph, because he shot with the owner of that company when he lived and Worked in Rockford, Illinois, where the company is based. The basic machine runs about $135.00, which is very reasonably priced for what you get.

If you google Chronographs, you can find others. I took a look last year and found 5 different companies, and prices that were generally a lot higher than the CE machine. The Chrony costs about $80.00, but it lacks some of the functions you get with the CE machine.

If you belong to a BP club, purchasing One good chronograph for all members to use is probably a more reasonable expenditure of money. You might talk to the club leaders about buying one for the club. I shoot a lot of different guns, when My back allows it, and reload for most of them. So, I have use for a chronograph more than most BP only shooters would. I found that using the chronograph shorted the time it takes to tune a load to a particular gun, and saved me money, and frustration at the range. Because of my bad back, walking or standing makes my time limited, so the Chronograph has allowed me to do some things I could not do otherwise. As popular as the machines have become as more companies have entered the field, and reduced the prices, you are likely to find some friend who has a chronograph already, tha you can borrow, or he will set up for you to use for the limited use you have for one. :thumbsup:

 

[Herb]

A friend just bought a Chrony from Cabelas. Had his mind set on a Pact until he read the feedback on Cabela's site, and the Chrony was much better liked. I haven't called this up, but it should help you decide.