Lyman GPR 50--.490 or .495 Balls

[FishDFly]

I have been saving information on the Lyman GPR 50 and one thing I cannot find, is what is the most frequently used/preferred ball size, .490 or .495?

The manual suggests .495.

I know there is a following by some to use a sligthly smaller ball size with thicker patching than to use a sligthly larger ball size and thinner patching.

I have a lot of .490 balls and .490 molds on hand.

The initially bore cleaning was done exactly as the Lyman manual calls for. I only shot it at 25 yards off the bench for 8 or 10 shots and accuarcy was less than what I had hoped for, but I have read that the accuracy should come around 100 shots or so.

I know, I know, that you have to work up a proper load, I am just trying to save some time in the heat and wondering if I am going to need .495s.

Thanks

RDE

 

[Deadeye]

Either will probably shoot as well as the other if you get the right thickness of patch. I use 490s in my .50s with .015 patch but I have one .50 that has a large bore that takes a .023
patch and is very accurate with it. I have 3 .62s
all different. With .600 ball one uses .007, one .015 and one .023. All shoot very accurate.
Accuracy is mainly in the ball/patch/lube combination. I use spit except for hunting.
Amount of powder has little effect on accuracy.
IMHO

 

[BrownBear]

Mine is indiscriminate between .490 and .495, as long I adust patch thickness. The .490 prefers .018 ticking, while the .495 likes .015. The .495 also likes .018, but it's a PITA to start them. I also like using .018 ticking because it's easy to find and cheap in fabric stores.


A few words of advice or encouragement on accuracy in the GPR. Even following Lyman's cleaning advice, you never seem to get all the gunk out of the bore. Get yourself a can of brake cleaner and use a few patches of that. Now your talking a squeeky clean bore that will shoot bunches better.

New Lyman barrels also tend to have sharp rifling and crowns, leading to lots of cut patches and diminishing accuracy. On the sharp crowns, be careful to have the patch evenly compressed around the ball as it seats, rather than allowing any folds. Now press firmly on your short starter rather than whacking it. You'll eliminate a lot of torn patches and fliers with that simple bit of care.

Now for the sharp rifling. You can use steel wool or green scotch pads on a jag to help take down some of the sharp, or simply shoot it awhile. I go for the latter. It takes a couple of hundred shots to really smooth down the sharp, but it's encouraging to watch accuracy keep improving with each shot.

If you pay attention to seating with that sharp crown and bear with the "break-in" period of Lyman barrels, accuracy is going to be everything you hoped for.

 

[bubba15301]

i used .490 rb in mine
sorry i sold it. i just got a lyman trade rifle in .50 cal -trade a bushnell scope for it

 

[jtmattison]

Mine prefers .495 and Wally World pillow ticking.

HD

 

[hanshi]

Use a good lube and use patch material thick enough, yet able to allow the ball to be seated without a lot of pressure.

I use .490 cast balls in a number of .50s and get fine accuracy. On a whim the other day i got out my caliper and measured a few. The several I measured were actually .493 - .495 (I turned them and measured from several angles). I'd say a good average diameter for them is around .493 or so. Go ahead & use your .490 mold. Just get a good lube & patch.

 

[Ken Rummer]

I use both. I like the tightest PRB I can get down the bore. The two ball sizes along with all the variation in patch thickness found in the fabric store allows more options to get the best PRB diameter for your bore. If there was only one ball diameter there would much fewer options and less chance of getting a combination that could drive tacks.

I don't think one size is inherently more accurate than another

 

[FishDFly]

Thanks to all for your insight, I will start with the .490s since I have them and the molds and play with patch thicknesses.

RDE

 

[cmdrted]

Just to throw my hat in the ring, I'm using the lee 490 rb and walyworld ticking. With 6/1 ballistol lube it shoots into a quarter with 50 gr 3f. The group stays pretty tight up to 90 gr but off the bench starts to smart my boney shoulders. I use the same in my GPR 50 flinter and it stays about the same size, although I'm new to flint and still wander off sites to watch the fireworks show before it fires!

 

[paulvallandigham]

Richard: When you get to the heavier loads( over 70 grains, ie. remember the .50-70!)I recommend trying the 2Fg powder instead of the 3Fg powder you are using. It will take the bite out of the recoil , even if you have to use a bit more powder to achieve the same velocities. These are hunting loads, and you don't need to be loading 90 grains or more in that rifle for casual shooting.

Oh, I found that if I use a Walter's Vegetable Fiber Wad ( 1/8" thick OP wad) on top of the powder, I get better gas sealing with heavy hunting loads, and a better burn of the larger granule 2Fg powder, so that there is no difference in the residue left in the barrel shooting 2Fg this way, compared to shooting my 3Fg powder. The OP wad also gives higher velocity, and lower SDV for more accurate groups at long range. The lesser recoil jab makes it easier for me to shoot a long range session to zero the gun in at 100 yds. and practice with the load before going deer hunting.

My hunting load in my .50 for deer is 75 grains of 2Fg, but I found I got the right amount of accuracy, without the recoil, that I got shooting more powder. Increasing the powder changed the trajectory by less than an inch- which I can not see or HOLD with open sights at 100 yds. The deer I have shot don't seem to notice that the ball is being pushed by less powder. The ball penetrates the deer's body completely on broadside shots.

My barrel is 39 inches long, and I have tested powder charge with both 2Fg and 3Fg from 50 grains to 100 grains, in five grain increments, in it at both 50 and 100 yds. I use a .490 ball in my GM barrel, but also tried the .495.

 

[hanshi]

I'm always glad to hear other shooters talk of the benefits of over powder wads. I've caught a lot of flak because my continued recommendations to use them. My chronograph tells me ballistics improve with their use and they do protect the patch and the powder both.

 

[paulvallandigham]

Our chronographs seem to be listening to each other! How eerie is that?? :shocked2: :rotf: :hatsoff: