Investarms 58 cal load question.

[snapbang]

My new (to me) Investarms 58 was built in 1977 or 1978. It is 15/16 across the flats. One of the members here suggested reduced loads for a barrel with thinner walls. The loads below come out of the Investarms Manual. Black powder only.

I intend to you Swiss ffg.

I really don't see any reason to load that much powder but does anyone have a reason to reduce these maximum loads???


.58 .560 Round Ball 110 grs. ------
.58 460 grs. Minie Ball 100 grs. -----

 

[snapbang]

bump

 

[Fastleo]

If it were mine I’d just follow the manual

 

[deermanok]

I've never run max powder charges in any of my sidehammer guns.
In my 50's, I think the max charge for round balls is 100, 105 grains of 2f.
The sweet spot for me seems to be right around 80 grains.
I think you could run something like 70 to 100 grains for good accuracy.

 

[snapbang]

I did send an email to the company. I really see no reason to use max.

 

[deermanok]

Absolutely no need to over power the 58.
The paper cartridges they used during the Civil War were only loaded with 60 grains of black powder.

 

[AfricaDouble]

My double .58 has a capacity max of 140
It’s very very accurate with only 75gr of goex and either a 280gr 8bhn prb or the Lee REAL 445 gr 9 Bhn
I’ve got 3 leaders express sights I can see over top of the ghost ring that’s set at 50 yards.

I have Swiss powder and will someday bump up the charge- yet Accurately placing a projectile of that size anywhere within 100yards is more than sufficient on most game.

 

[snapbang]

I have talked with other members here and no reason to shoot more than 80 grains with ball or conical unless I get better accuracy. Then I will nor exceed InvestArms 110 grains for PRB and 100 for conical.

Thank you.

 

[AfricaDouble]

Unless I want Flat trajectory for 120-135 yards… I see no reason to crank up the powder.

At a well known shop- one of the employees said something that resonated well with me.

“ Most guys that don’t get good accuracy,Is Becouse they start off with to much powder”

 

[snapbang]

Good tip, think 80 grains of swiss ff is a good starting place? or should I start with less???

 

[AfricaDouble]

I would start at 70 grains. You never know, could be very accurate. Plus Swiss has a bit more kick than Goex. I’d be shooting more grains if it was as accurate- just haven’t worked it up yet.
I certainly would prefer a flatter trajectory- yet that’s a afterthought when I hit bullseyes on occasion with a double at 80 yards.

 

[snapbang]

70 grains it is. After I get an accurate load Ill run it over a chrony and get a trajectory for it. Round ball BC = .08????

 

[AfricaDouble]

Roundball BC ? Um… “Big Clobber?” Just kidding, I don’t know. I do know you can Chrono and then get digital graphs per each .5 grain increments….
Yet I will tell ya, probably 1100fps and best to simply shoot it. To many variables to account for. Holding rifle on bench in sandbags. Or standing with increased muzzle raising- after hammer drops. All will change impact points.

 

[snapbang]

 

[AfricaDouble]

My 9.5lbs double with 29” brl and my 7 lbs T/c Big Boar with 26” brl impact different with same charge and Projectile.