GM .62 Maximum Loads

[damron]

My .62cal is a smooth rifle with a Rice barrel having a 1&1/8" breech...and doing load development for woods hunting on the east coast the most I ever tested was 120grns Goex 2F, settled on a moderate 110grn charge for whitetails.

I am just working up loads for my .62 cal (.615) GM barrel.All i have is a .575 ball mold right now.With 90g of FF Goex and denim patch i am getting about 6" at 50 yards for 5 shots.How much better can i expect? Should i get a .590 to .600 ball mold and go with thinner patches?

George

 

[roundball]

My .62cal is a smooth rifle with a Rice barrel having a 1&1/8" breech...and doing load development for woods hunting on the east coast the most I ever tested was 120grns Goex 2F, settled on a moderate 110grn charge for whitetails.

I am just working up loads for my .62 cal (.615) GM barrel.All i have is a .575 ball mold right now.With 90g of FF Goex and denim patch i am getting about 6" at 50 yards for 5 shots.
How much better can i expect?
Should i get a .590 to .600 ball mold and go with thinner patches?
George

My personal opinion is that .62cal smoothbores (smooth rifles with rear sights) should shoot about like a rifle at 50yds.
There are so many variables, particularly with smoothbores, that I couldn't tell you what "would work" in your particular barrel.
I will say that I've always leaned towards thicker patches...for example, my .62cal is a true .620" and a .600"/.022" PRB combination does best for me in that barrel.
(2.5" at 50yds sitting down shooting from a hunting position like leaning against a tree.)

Another thing helps my accuracy is that I drive the PRBs under a pretty strong head of steam so they don't slow down much and start wandering by the time they get to 50yds.
Doing load development for this deer load, as I was stepping up through 10grn increments of Goex 2F, when I hit 110grns the muzzleblast started sounding like a "crack" and the group size shrunk in half. 120grns didn't make it any better, and trying 100 again it started to open back up some, so I settled on 110grns.

Based on the above, all I could do is suggest how I'd approach it which would be to try something similar in your .615" bore:
.020" Oxyoke patch and .595" ball. (Oxyoke .020" patches actually seem to measure .022")
(You can order the patches and a trial bag of 25 .595"s from Track of the Wolf to experiment with).

Test 3 shot groups of 80/90/100/110/120grns Goex 2F (or equivalent) at 25yds, then take the best one and move to 50yd...step up the powder charge as you need to.

 

[roundball]

My .62cal is a smooth rifle with a Rice barrel having a 1&1/8" breech...and doing load development for woods hunting on the east coast the most I ever tested was 120grns Goex 2F, settled on a moderate 110grn charge for whitetails.

I am just working up loads for my .62 cal (.615) GM barrel.All i have is a .575 ball mold right now.With 90g of FF Goex and denim patch i am getting about 6" at 50 yards for 5 shots.
How much better can i expect?
Should i get a .590 to .600 ball mold and go with thinner patches?
George

My personal opinion is that .62cal smoothbores (smooth rifles with rear sights) should shoot about like a rifle at 50yds.
There are so many variables, particularly with smoothbores, that I couldn't tell you what "would work" in your particular barrel.
I will say that I've always leaned towards thicker patches...for example, my .62cal is a true .620" and a .600"/.022" PRB combination does best for me in that barrel.
(2.5" at 50yds sitting down shooting from a hunting position like leaning against a tree.)

Another thing helps my accuracy is that I drive the PRBs under a pretty strong head of steam so they don't slow down much and start wandering by the time they get to 50yds.
Doing load development for this deer load, as I was stepping up through 10grn increments of Goex 2F, when I hit 110grns the muzzleblast started sounding like a "crack" and the group size shrunk in half. 120grns didn't make it any better, and trying 100 again it started to open back up some, so I settled on 110grns.

Based on the above, all I could do is suggest how I'd approach it which would be to try something similar in your .615" bore:
.020" Oxyoke patch and .595" ball. (Oxyoke .020" patches actually seem to measure .022")
(You can order the patches and a trial bag of 25 .595"s from Track of the Wolf to experiment with).

Test 3 shot groups of 80/90/100/110/120grns Goex 2F (or equivalent) at 25yds, then take the best one and move to 50yd...step up the powder charge as you need to.

 

[damron]

thanks for the info.I hate to buy cast bullets but the 'Tracks .595 balls maybe the way to go before i buy one.

George

 

[damron]

thanks for the info.I hate to buy cast bullets but the 'Tracks .595 balls maybe the way to go before i buy one.

George

 

[MercerLake]

:v Dameron, I would suggest you buy some .590" and some .600" balls before investing in a mold. Try the larger balls with 100-120 grsFFg the 50 yard groups should be be in the 2" range. Possibly even better if you have a rear sight! :v

 

[MercerLake]

:v Dameron, I would suggest you buy some .590" and some .600" balls before investing in a mold. Try the larger balls with 100-120 grsFFg the 50 yard groups should be be in the 2" range. Possibly even better if you have a rear sight! :v

 

[roundball]

thanks for the info.I hate to buy cast bullets but the 'Tracks .595 balls maybe the way to go before i buy one.
George

That's one of the nice things about the 'trial packs' at TOW if you're also going to be ordering and paying shipping/handling for something else.

But frankly, for the same money you can get 100 from a commercial caster in GA by the name of Eddie May that you can buy directly from...about half the price of everyplace else.
(Qty 500 of .600" balls a year ago was $1100/100)

Eddie May Cast Round Balls
159 Ridley Rd.
Chatsworth, GA. 30705
706-581-8225
“Best Quality Round Balls, Minnie, Rifle Bullets and Modern Cast Bullets”
Please Call or Write to place Order
(Eddie does not have a website or use Email)

 

[roundball]

thanks for the info.I hate to buy cast bullets but the 'Tracks .595 balls maybe the way to go before i buy one.
George

That's one of the nice things about the 'trial packs' at TOW if you're also going to be ordering and paying shipping/handling for something else.

But frankly, for the same money you can get 100 from a commercial caster in GA by the name of Eddie May that you can buy directly from...about half the price of everyplace else.
(Qty 500 of .600" balls a year ago was $1100/100)

Eddie May Cast Round Balls
159 Ridley Rd.
Chatsworth, GA. 30705
706-581-8225
“Best Quality Round Balls, Minnie, Rifle Bullets and Modern Cast Bullets”
Please Call or Write to place Order
(Eddie does not have a website or use Email)

 

[BrownBear]

I'll fix your typo roundball- I bet that's $11.00/100 in orders of 500.

Other than that I have to back up everything you say about what's happening in loads, in my experience with my GM 62 capper barrel anyway. I tried some .575's and didn't get the accuracy I wanted even with double .018 patches. Only different thing I'm doing is I started shooting a .600 with a .018 patch (tight fit) when my .595's ran out. Getting a Tanner mold in .595 is on my list, but since I'm shooting so little RB through it I keep stalling.

Powder charge? It was 110 gr of Goex 2f until I tried the 1f I prefer with shot. Maybe no coincidence, but that load settled in at 120 grains. I've been shooting 1f rather than 2f ever since, because that's what's usually in the horn on my 62 cal kit.

 

[BrownBear]

I'll fix your typo roundball- I bet that's $11.00/100 in orders of 500.

Other than that I have to back up everything you say about what's happening in loads, in my experience with my GM 62 capper barrel anyway. I tried some .575's and didn't get the accuracy I wanted even with double .018 patches. Only different thing I'm doing is I started shooting a .600 with a .018 patch (tight fit) when my .595's ran out. Getting a Tanner mold in .595 is on my list, but since I'm shooting so little RB through it I keep stalling.

Powder charge? It was 110 gr of Goex 2f until I tried the 1f I prefer with shot. Maybe no coincidence, but that load settled in at 120 grains. I've been shooting 1f rather than 2f ever since, because that's what's usually in the horn on my 62 cal kit.

 

[roundball]

I'll fix your typo roundball- I bet that's $11.00/100 in orders of 500.

Yeah, looks like I didn't get enough pressure on the period key for a decimal point... :redface: Thanks!

 

[roundball]

I'll fix your typo roundball- I bet that's $11.00/100 in orders of 500.

Yeah, looks like I didn't get enough pressure on the period key for a decimal point... :redface: Thanks!

 

[damron]

My 62 GM sort of came to life a bit .it took a .600 ball with thin .008(compressed measurement) tight weave patches and 100-120g of Pyro RS or Goex FF(both shot the same)it loads with the ramrod and no starter and thats kind of nice


The taped over shots were when started with a backed down load to 70-80g to reduce recoil. It wouldn't hold an 8" group.I taped them up and went back to the 100-120g loads with Pyro RS.I ran out of patches and shot the last 5 with unburned but used patches from down range(bad idea as they loaded too easy).I have work to do but its getting better.

George

 

[roundball]

Sounds like you're on the right track with it.
That was my experience...the faster I pushed them the more accurate they were...good work!

 

[damron]

OK went out again today with the same loads(100g Goex FF this time) and got inconsistent accuracy.One group was 2.25" The next was 4 into 3" and one out to make it 5".Swabbed the barrel and the next group had 4 into 4" and one drop waaaay low to make it a 7" group.Next one was and even 3.5" but hollow.Pretty sure my cast balls are uniform and my loading mechanics are sound??

is this just the way of the smoothie boar??

George

 

[roundball]

OK went out again today with the same loads(100g Goex FF this time) and got inconsistent accuracy.One group was 2.25" The next was 4 into 3" and one out to make it 5".Swabbed the barrel and the next group had 4 into 4" and one drop waaaay low to make it a 7" group.Next one was and even 3.5" but hollow.Pretty sure my cast balls are uniform and my loading mechanics are sound??

is this just the way of the smoothie boar??

George

Not in my opinion...looking at your previous trip, you know the gun & you are capable of better...and if you set aside the individual flyer from each of those groups, the basic groups from this trip are still pretty decent.

Each individual flyer could be nothing more than a slightly off-day this trip from the shooter's involvement...(it happens)...or IMO, too thin of a patch. Once you finalize the right combination of powder/patch thickness/ball diameter, it should lay them in there all day long. IE: You could be losing gas seal right at muzzle exit and a blowout occurring at one tiny spot, nudging the ball off course just as it's leaving. So for me, the first order of business would be to figure out / eliminate the odd flyer.

Personally, I've never had good success with a thin patch in anything I've tried, rifle or smoothbore, and I've learned not to waste time & money trying to make them work...in all my experimenting with smoothbores, the best most consistent accuracy has always come with a .020" under bore size ball and a thicker (.020"-.022") patch.
But that's just been me / my experiences...

 

[Deadeye]

Normally I use a ball size that requires a thicker patch too but when I got a GM .62 barrel that measured .610 and I had a .600 ball mould I had to go with a thinner patch, went to Walmart, got some super muslin (.007 by my measure)and it shoots wonderful, that muslin is so strong it can be shot several times (washed in between because I spit patch). My regular load is 70 2F but I've gone up to 140 gr. 2F with the same accuracy. 3" offhand is normal at 50 yds. I know I should get a smaller ball mould and may sometime but this muslin shoots so well and ir was only $1.27 per yd.
Deadeye

 

[Rifleman1776]

I've never had good success with a thin patch in anything I've tried

My first and second rifles in 1970 (a CVA 'kentucky' and a TC 'hawken') had rifling so shallow it/they were almost a joke. Don Davis (he of 'one of the great characters of all time fame'), suggested I use airplane cloth. It is very-very thin and amazingly tight weave and strong. It worked just fine for patch cloth in these shallow grove rifles. Dunno :idunno: if it is still available, thanks to the FAA.

 

[Dphar]

1137 GB quality as used by GM will not be damaged by any BP load unless very thin walled. I know that when Shiloh was using it for Sharps barrels it was tested to 50K with no problems and that a 45-120 will not stick cases at heavy overloads of smokeless under a 500 gr jacketed bullet.
This is not the case with the cheap cold rolled steels used in many "custom" ML barrels, however.

So far as the "Forsythe" rifle loads often used today.
Shooters should note that Forsythe used 137 gr in in his 69 caliber rifle. This is very close to the 140 I shoot in my English style FL rifle that uses a 16 to the pound ball (Forsythe used a 15 to the pound).
It has a 80" twist with .008" deep grooves and will keep all balls touching at 50 yards and is accurate enough for deer to about 200.
Making a 144" twist 62 is too silly for words IMO. Thinking that its possible to increase velocity by decreasing friction is 180 degrees out. Forsythe was wrong in this and this was known by gun makers of the time. They used to not polish the bore for a few inches up from the breech to increase velocity in shotguns. They would also slightly roughen the last few inches to "retard" the over powder wads so muzzle blast did not accelerate them into the shot column. But this makes cleaning more difficult.
I see no point in twists slower than 96" in any rifle unless its perhaps an 8 bore or larger.
But as usual someone thinks that if "X" is good then twice "X" must be better. This is not the case when speaking of powder charges or rifling twists in hunting rifles.
I would bet that a 72" twist 62 will shoot 200 gr without stripping the patch if loaded right.
Click the link for a slo-mo of my 16 bore recoil.

Dan
http://s72.photobucket.com/albums/i199/DPhariss/Video 1/?action=view&current=SLOWMOTION.mp4