changing point of impact.

[Black Jaque Janaviac]

OK, my TVM Early Virginia is giving me fits.

When I first got it I sighted it in.  Filed the front blade down, and merrily began harvesting deer.

Then I began missing targets, and found that my point of impact was 11" high at 100 yards.  

So I purchased a new front sight blade and resightted it in.  Next season I missed another easy shot.  I fired the next shot into a stump and found that it is hitting 3" low at 30 yards!

Feeling frustrated, I put the flintlock away for a few months while I cooked up some loads for a paper-patched .35 Whelen.  Then just yesterday I took the gun to the range, with a file, all set to raise the point of impact.

Now it's shooting dead on at 50 yards and about 1.5" low at 100 yards!!!!!!

ArrrGH!  What is going on here?

It is a 42-inch Colerain D-weight, .54 caliber (heavy barrel), with a full stock.  

The only thing I can figure is that the stock and or barrel are straining each other as temperatures change along with humidity.   Any other possibilities?

[Idaho Ron]

I guess this might sound dumb but could your stock be warping or swelling?   Ron

[KY Ratshooter]

A properly made fullstock rifle should not have enough wood on the forend to warp a c-weight barrel.  

If the stock does have excessive wood, re the lugs for the pins or wedges holding the barrel to the stock slotted for expansion?

This sounds like a loading or componant problem.   Same powder measure?  Same patch/ball combo?  Same can of powder?  

Is the change in POI steady once it occurrs?

Just changing powder brands or case lots of powder can shift POI this much.

[Black Jaque Janaviac]

If the stock does have excessive wood, re the lugs for the pins or wedges holding the barrel to the stock slotted for expansion?

Not sure what you mean.  The lugs just have a 1/16" hole for the pins.  They are not what I would describe as slots.

How much wood is too much?  How would I go about altering the lug from holes to slots?

Same powder measure?

Yes

Same patch/ball combo?

Yes

Same can of powder?

No, but the same lot #.

Is the change in POI steady once it occurrs?

Yes.  I get satisfactory groups.  Then I file the sight to bring POI to POA.  Then everything is wonderful for a while.

Just changing powder brands or case lots of powder can shift POI this much.

 True.  I would hope that you wouldn't have this problem with Swiss powder.  That stuff is generally top quality.

[KY Ratshooter]

Knowing TVM products I am sure that the amount of wood you COULD remove from the fore end is minimal.  They take it down about as far as they dare although most custom builders go about 1/8" along the barrel.  The barrel actually supports and protects the wood.

In this situation the only real "warping" that can take place is in the length of the fore end.  For this reason, most good builders will slightly slot the holes in the lugs where the pins pass.  That allows the wood to swell and contract slightly without putting any preasure on the barrel.

Since your problem seems to be vertical changes of POI this may be your problem.  A few minutes work with a dremil tool, or even a drill, should solve this problem.

This is one of those places where the need for production speed/close profit margin vs. giving the best product for the money cross paths.  TVM makes a good gun but they can not do all of the tricks a custom builder uses to insure ultimate shootability and still sell at the prices they charge.

Ratshooter

[huntnut]

I'm having the same problem with my lyman gpr. It is a new gun, I took it out shot it around 50 times the first couple days and was shooting 3" high at 100 yards, took it out a couple weeks later, same powder, patch, ball, caps, and now its shooting 18" high at 100 yards, The only thing I can figure out is that the lands have smoothed out so there is not as much drag on the patch and ball. I have little more then 100 rounds through the barrle so far, I havent been out again to see if the POI has changed again. My biggest problem is my rear peep sight is adjusted all the way down so if the POI stays the same I well have to get a taller front blade.

[lostid]

it's your cleaning and patch ball combo;
too many variables,,
 Untill you deside to doo the same thing each tyme,,EACH time you shoot. No one can help you too become a proficiant,. dedicated, accurate shooter.
Black jaque,,I've watched you for years. You have alot of answers. It does my heart good to see you ask, , friend :grin:

[lostid]

I have little more then 100 rounds through the barrle so far.

 Good, shoot another one hundered ball,,then sight in (truth)
 Then,

[fffffg]

if the gun is for hunting,, .... when you go to the range shoot at the distance your comfortable with..  shoot a five shot group in the manner you will be hunting..  mark where each the first five shots hit on the target in order, mark with the  date,  powder amount and type,  temperature, patch type, ball diameter, lube, and how you wiped for each of the five shots..  put this first target of the day in a folder..  do this each time out for a year..  then you will be able to look at your targets and see what is going on..  usually a high shot is on a dry day on the 2nd or third shot if you arnt wipping..  the lowest shot could be your first shot..  probably dfferent for every gun, and different for each load for that gun..  ideally a good load will keep them in the kill zone without wiping for two shots at 75 yards in cold temps and warm temps shooting the way you do in the field.... ball/ patch /lube /combo,  barrel length, twist, groove depth, powder granulation, velocity, gun weight, fouling, temperature, humidity,  and your hold all cause  variables on this..  dave..

[Swamp Yankee]

Lostid brought up the point about being consistent.  I was just wondering if you seat your ball on the charge with the same pressure each time. I know it sounds like a dumb question. I watch alot of the guys I shoot with.... as their barrel gets dirtier they require more force to seat the ball and I will catch them really driving the ball down with great force. [some of them aren't big on the ocational cleaning patch]  anyway it was just a thought....Jim

[yottey]

Just send it down just south of Adams to me and I'll fix it and send it back in 5 or 6 years !yottey
P.S. free of charge

[captchee]

Im with rat shooter . There shouldnÂ’t be enough wood to effect the barrel however I would still suspect this being the case  for being off the mark at distances  . I would not accept this for a reasoning for your  being low at 30 .  I would suspect unless your benching the rifle this to be barrel drop . Your expecting   to be off so your looking for it  ever so slightly .
 I also agree that a good smith will elongate the  barrel lug hole to allow for expansion.  You donÂ’t here folks talk about that much , As the barrel heats up  you will get whatÂ’s called walk . IE the barrel will naturally draw in one direction  kind of like a machine gun spray  .

 Another thing you have not said and has not been touched on is the  humidity of  the time of shooting ..
 Humidity plays a very big part on  pressures  and burn rates . This all converts to muzzle velocities .
 I will say I have never heard of it effecting  to this degree but  it may be something to look at . Especially if you sighted in on a spring morning and then  next  shot on a 98 % RH fall day .

 You also did not say if this was a kit you put together or a  completed  new rifle  or a used one  put together by someone else .
 Unless it was  a manufacture rifle I would suspect improper beding of the barrel into the stock . There is always a chance it came from the manufacture or builder that way such as with  Lyman  but  I wouldnÂ’t think so with the TVM

[Black Jaque Janaviac]

Another thing you have not said and has not been touched on is the  humidity of  the time of shooting ..

Humidity varies considerably in Wisconsin.  I would not think this would be the factor as no one in Wisconsin could rely on their MLs.  We'd all be swapping out our front sights every two weeks.

You also did not say if this was a kit you put together or a  completed  new rifle  or a used one  put together by someone else .

It was an in-the-white kit.  Matt Avance did the work I think.  I blued the steel and finished the stock.