Shallow groves??

[Needstuff03]

I recently picked up a hopkins allen underhammer in 45 caliber, its stamped model 25 on one of the flats. I have noticed the rifling is very shallow. How will this affect round ball accuracy i have read shallow grove does better with conicals is this true. This is all new to me

 

[nhmoose]

IMHO they will be shallow and full of reamer marks. Won't matter they will shoot well with either. You will need .433 balls for them. Hornady sells that size.

 

[Needstuff03]

Thank you

 

[smo]

I have a Hopkins Allen under hammer in .36 cal.

It’s a great shooting gun.

 

[Needstuff03]

Thats awesomeness...

 

[Wildrangeringreen]

Shallow groove is fine, I go with .005"-.01" under bore with the ball, .01"-.015" cloth patching or paper patch the suckers with printer paper. I have found that shallow groove barrels are easier to find a variety of loads that work well than deeper groove barrels.

Shallower grooves require thinner patching, and when combined with a close to bore size ball, require the ball to deform less to upset into the grooves than deep ones do. Less deformation tends to be a little more consistent than more deformation.
Play with it a bit and I think you'll be pleased with that underhammer rifle!

 

[andy52]

It may be a Forsyth style of rifling, you see it more on large bore guns but I see no reason it wouldn't work with smaller ones.

 

[rusticbob]

Thompson Center has always had shallow grove rifling on their std Hawken and Renegade barrels. They still shoot great with both PRB and conical. Find the right patch and go shoot it!

 

[oldwood]

The original H and A under hammers from the late 1960s , were sold in dept, stores like Pennies , and others. Around central Pa. , there was a hardware . store also that had a few. They had Numeric Arms barrels that were shallow grooves. The bores ran slightly smaller in size because the rifling machines used bore sizes for modern cartridge bullets. They shot very well , as long as they were patched a little tighter , than a modern m/l barrel of today . The mold sizes were slightly smaller as well. Back then in the late 1960's ,, the only barrel MFGing folks were Paris , Bill Large , Douglas , ,and a couple others

 

[Col. Batguano]

what is the twist rate of those guns?

 

[user 34300]

Shallow is good, up to a point. I have made several rifles with barrels intended for 45-70. They shoot very accurately and are easy to work up a load.

On the other hand the trend is toward very deep grooves and sometimes narrow round bottom grooves. IMHO this a very poor way to make a barrel. IN my experience the accuracy is worse. Finding an acceptable load is difficult. Loading is much more difficult if you want to seal the bore with the patch in the grooves.

At the end of the day most shooters are not very interested in pinpoint accuracy. So, it does no matter for them.

 

[dave951]

You should see how shallow the rifling is on Civil War guns and they are quite capable of outstanding accuracy

 

[EC121]

Deep groove rifling is all marketing. .004" to .008" is plenty.

 

[Needstuff03]

That all makes sense, thanks guys

 

[Johnny Tremain]

Button rifling is just a cheaper way to make barrels. Marlin made it famous.
As far as 45/70, I shoot lubed grooved boolits and smooth walled paper patched boolits.
All 3 of the 45/70s are shallow grooved and preform very well.

My flintlock has a deep groove Rice barrel. Within distance it will out shoot the 45/70s easy.
But then thats a 180gr patched round ball VS a 430gr flat nosed traveling slower than the round ball.

 

[oldwood]

Don't mean to upset the discussion about shallow grooves vs. deeper grooves. It takes deep grooves to deliver larger heavier balls , greater distances , accurately. Any small r/b caliber , with no wind , will put balls on target out to 100 yds. . .50 cal. and above needs more powder to push a ball on a flatter trajectory to be usable beyond 100 yds.. .........Deeper grooves with patched round balls , not slugs of any kind. That's a different science. Slugs do not use patches and are shot naked , shallow grooved rifling needed. Slugs don't do well in deep rifling.
There is a lot more information that can be interjected in this deep groove/ shallow groove discussion to prove a point. .................No offence to anyone. Been messing with this whole science for 50+ years , and still can't say i have a good grasp of it. The forum has helped , because I can tie another guys findings to what I have done............oldwood

 

[Rifleman1776]

I had an ml shop in the early 1970 and sold H&A underhammers. My family also shot them, we had several. They were very accurate. My wife won a boat load of matches with her short buggy rifle. We never had trouble loading with popular cloth for patching, like ticking. That was a long time ago so I can't say for certain what size ball I used. But for my other rifles I used .440" or .445" round balls and don't recall casting anything different for the H&As. But, the first barrel on my TC 'hawken' had very shallow rifling and I used airplane cloth for patching on that one. Side not: when I moved from Indiana to Arkansas some saw my heavy barreled H&A bench rifle and wanted to buy it. I declined. But, he bugged so often I finally consented and sold it. Big misteak it was a winner in competition.

 

[oldwood]

There were several guys and a gal had H&A rifles in the early 1970's. They shot well , at the shooting comp.'s , and one guy used to shoot cedar arrows from his.

 

[ILoveMuzzleloading]

Shallow rifling definitely isn’t a problem, will be easier to clean too. Enjoy!