New Kibler SMR .40 tight bore

[AZshot]

I just finished my Kibler Appalachian rifle (term I prefer), and loved the experience of building it.  It is a fine, high quality set of components.  Wood was from Allen Martin.

But when I went to shoot it with .395 balls and the thinnest patch I could find, it would not load with that combo.  My thin patches were about .018.  I haven't tried to measure the bore, but it's feeling like it's barely .400.  Is that normal?  I read of people using .395 balls with .020 patches.  There is no way in my rifle, I couldn't even get a ball started hammering with my ball starter.  It just deformed at the muzzle.  The bare .395 would roll down the bore, seems to have a hair of clearance over the lands.

I've ordered some .380 and .389 balls.....but wonder.

[Eric Krewson]

I ran into the same thing on the TN rifle I built with a GM straight barrel. I tried .395 balls and an .18 patch, it was a no-go without a hammer. I bought a .390 mold and could load the rifle easily.

[Daryl]

Those Kibler kits make wonderful rifles.
The .40 Goodoien barrel I had, was .398".  The mould I had said .395", but case .398". I used those balls, cast in "pure" lead (at least plumbers at 98%) with the 10 ounce denim we got
back then. It measured .0225". I had no trouble and didn't even need a starter, as pressure along would form the ball & patch into the bore. It was just easier to use the starter, giving the
knob a smack with the palm of my hand. That bore had wide grooves and quite narrow lands.
I also used a Lyman ball mould I sent to Hanshi, which cast a .400"x.400" ball in one cavity and a .400" x .396" ball in the other cavity. The .400"x.400" ball loaded just fine with the same patches
and also the mattress ticking patches we had at that time, that measured .0235".
The muzzle is why I/we were able to use these combinations. Once started the ball would do down with only 2 or 3 fingers on the rod.
This is that barrel's muzzle, the MOST important feature of the barrel.

[bluenoser]

My 30+ year old .40 with a GM barrel loads comfortably with a .390 ball and .016" patch. Just a light whack on the ball starter using the palm of the hand gets it started.  Can also start with the ramrod, but it is a bit of a tussle.

[AZshot]

Thanks for the good dialog....I'm looking forward to the new, smaller balls that are coming.  Once I settle on a size, I may get a mold and make my own so I'm not beholden to any manufacturer. I gently polished the crown, but didn't try to cone it.  Too much an advanced technique for me...and I could do it later if I want.

[Bob Roller]

Find a small hole gauge and a micrometer and stop the guessing.Use the "mike"to measure the ball as well.

Bob Roller

[AZshot]

I'm measuring .397 Land-to-Land with a caliper. 
Balls measure .3953

So about what my calibrated eyeball was seeing.  Barely a sliver of room between the naked ball and the lands. 

[Spalding]

My. 40 Kibler shot well with a .395 ball and .018 ticking. 40 grains of 3F.

Bob

[ScottH]

I'm using .395 diameter Hornady swaged balls with pocket drill at 0.020 thick and mink oil/grease for lube. it is tight at the muzzle but once started it goes down to the powder fairly easy with the hickory rod or a range rod. My barrel I believe is a Rice barrel. It has narrow lands and wide grooves. I was working on my Kibler almost exactly one year ago.

[AZshot]

There is no way you're gonna get a .395 ball down this barrel, except with a patch thickness of .001, less than tissue paper.  Ain't gonna happen. 

The new ones are using Green Mountain barrels, and Kibler rifles them in house in .40 and below. 

[bluenoser]

That is interesting.  I thought Kibler was profiling the exterior of Green Mountain rifled barrel blanks.

[Daryl]

Thanks for the good dialog....I'm looking forward to the new, smaller balls that are coming.  Once I settle on a size, I may get a mold and make my own so I'm not beholden to any manufacturer. I gently polished the crown, but didn't try to cone it.  Too much an advanced technique for me...and I could do it later if I want.

AZshot - have another look at my muzzle. It is not coned as the "crowning" is only 1/8" deep to the full bore size. Cones have tapers to the lands from below the groove diameter to the bore
by up to 1 1/2", depending on who did it and with what.
The crowning I have, the angles used, are the same angles used in metal forming dies made by Corbin in the States. I have tried to copy/emulate those was we are forming a patched ball into a smaller diameter, ie: drawing the materials to form into the smaller groove diameter.
If you measure groove depth, you compressed patch and ball diameter should be larger than the groove diameter by .005" or more for the best shooting and cleanest shooting bore. No wiping necessary for an entire day's shooting.
You muzzle looks almost exactly like a machined muzzle. It needs some work, imho. I also see narrow grooves and wide lands. Not the best design today, but certainly usable with snug loads.
Here's one my bro did;



Here's one by DaveC




All of these load easily with tight combinations. Many guys here are doing this now and are reaping the rewards, go shooting, not cleaning
until after the shooting is done.

[MuskratMike]

I have a Kibler SMR that Jim put together for me several years ago. It is a .40 caliber. I have only used .395 balls and red stripe ticking (.012-.015) with various lubes it has always loaded easily with a short starter and the ramrod Jim supplied.

[WadePatton]

Bores are always going to vary slightly within specifications (tolerances). Adjust with a smaller ball because thinner patching is usually the wrong answer. Easy peasy.
That's why I don't buy a mold until I'm sure of the diameter I'll be shooting.

[AZshot]

Thanks all, I'll report back what I find with the .380 and .389 balls....

Thanks Daryl too, I should smooth up my muzzle like you show. 

[Kurt]

When I began shooting my Kibler 40 SMR I used a .495 ball and a .015 patch which loaded easily enough but I wanted a tighter patch in an attempt to improve accuracy. The .018 patch I then tried was hard to load and I discovered that if I used a smaller diameter ball starter it was easier to get it going. That combo of .395 and .018 with 50 grains 3F is the ticket with the small starter.

[togo]

My Kibler SMR 40 has the Rice 1:48 barrel. It loads well with .395 balls with .018 patches lubed with simple green and water. It is groups well and is very accurate with 40gr of GOEX 3f. I tried a .400 ball but that was way to tight.

[Daryl]

This barrel has a .398" bore, with .418" grove diameter (.010" deep rifling)

I used a .400" ball and a .0235" mattress ticking patch in this barrel and loaded it with just pushing down hard on the starter's knob, with the 3/8" cupped brass peg on the patched ball.
This actually makes a slightly elongated round ended slug out of that ball.  The normal ball I used, was from a .395" Lyman  mould, that cast a .398" x .398" ball. It loaded quite similarly and
did not need a short starter. It could be loaded into the muzzle with just a choked up ram rod.
The pure lead ball and patch conforms/forms into the bore. From there it was short started - ie: pegged 6" down the bore, then pushed the rest of the way onto the
powder with the rifle's 3.8" hickory rod in 2 or 3 tap/pushes.
A well 'shaped' crown is vital.
That same day I tested loading without smacking the starter's knob to get the patched ball into the muzzle, Leatherbelly, our late friend had his .40 made with a cone an inch or so deep and could not load the same ball and patch even with a starter. I tried his rifle with the starter and it was very difficult to get the patched ball started into the bore. I surmised this was due to the longer friction surface of the gradual cone.
Cones do not make it easier to load tight combinations - at least in his barrel. Physics indicates the long friction surface creates more resistance then the shorter crown to the forming of the patch and ball. Corbin's metal forming dies have this same angle and radiused surface. I merely duplicated it and it can be done with the end of your thumb and some emery or wet/dry paper.
The combination I used,  measures: .400 + .0235 + .0235" = .447" - which is .447" - .418" = .029 total compression in the bottom of the grooves = .0145" in the bottom of each groove.
THAT is a "tight" load, yet doable with no more than a 3/8" hickory rod.