Things that make me go,..Hmmmm!

[Picknlittle]

Went to the range today with my CVA .50 cal. inline.

I have recently begun shooting 150 gr pyrodex loads with 250 gr sabots. The group of the first five shots was nice,..about 1.5 inches, but 3" high and 2' right. I made my scope adjustments and the first two shots just left of center about 1/4 inch apart. Then stuff got weird. The next two shots were 8 and 6 inches low and 2 inches right! What the heck!??

Now keep in mind that I am repeating the same steps between shots with all groups. Wet patch, dry patch, load three pellets, bullet, tamp.

The out of the clear blue I'm back to an inch left of center!

Any ideas on what's happening?:banghead:

 

[Jamie C.]

Could be your scope isn't holding it's adjustment?


J.C.

 

[Bezoar]

sabots can have an impact on your accuracy
cleaning can be an issue as well
you may not be getting the same amount of combustion in the 3 pyrodex pellets with everyshot.
I stopped using more then 2 pellets when i figured out that the glowing blob of flame going downrange was the3rd pellet burning out side of the barrel.

 

[Picknlittle]

I 'm not seeing any extreme muzzle flash or unburned residue. My groups are actually tighter with three pellets and about four inches higher POI. The scope is a POS BSA, but unlike the episode I had with a BSA on my 30-06, this one returns to center as a group. It's like there are a couple of belly flop shots then back to grouping.

I'm thinking I may be leaving a drop or two of TC bore cleaner in the barrel that the dry patch doesn't collect. Could be moisture fouling the first powder pellet I suppose.

 

[Double Naught Spy]

Loose scope

 

[Picknlittle]

Scope is tight.

 

[Double Naught Spy]

Loose shooter.

 

[jrfoxx]

Loose scope

Scope is tight

Loose shooter

haha, that's just freakin' funny!

ok, sorry, you may return to the regularly scheduled thread now....

 

[Picknlittle]

I'm pretty sure there is a malfunction in the target acquisition and aim control mechanism that limits critical accuracy and contributes to POI drift, but we're talking an inch or so at 100 yds,....not a freakin foot fer cryin out loud!

 

[mykeal]

Come on, guys, it's obvious....

Geez, this isn't that hard to diagnose. Clearly the target is moving. Why is that so hard to figure out? Happens to me all the time. You just need bigger nails to hold it down. Ten inch landscaping spikes should help...about a dozen of 'em.

 

[Picknlittle]

As a precaution, I'll give the landscaping nails a shot, but since these issues are coming up while resting on sand bags, I'll assume that I'm maybe leaving some moisture in the barrel. I'll try changing my pre shot routine to include brushing instead of wet patching.

 

[Steve499]

I've had stuff like that happen, too. I decided that since it was only when I was shooting the only gun I own which has a BSA scope mounted on it, the internals on my scope had a demon or something. The scope is tight, so that's not the problem. BSA may be a good brand but I sure won't ever pay for another one.

Steve

 

[O.S.O.K.]

my take

What I'd do is take the scope off and shoot the same loads and see what kind of results you get. If you get consistent results without the flyers then you've solved the mystery.

I strongly suspect the scope - BSA is a good inexpensive scope from what I've read but they aren't as reliable as say a Nikon Prostaff, Weaver or Simons prohunter for example - brands that you can get for $150 and that will perform very well. I have all three in addition to TC, Leupold. They vary quite a bit in optical quality but all hold their zero.

 

[DrLaw]

Smaller rifle, same problem. Ruger 10-22. New BSA Scope. Got it sighted in, I thought, and then I started to have shots flying all over the place. Scope was nice and tight. No rattle, nothing wrong inside. Could not figure it out, until I got the mount to move. Had to take everything off and redo the mount, as it had come loose, but not enough to notice off-hand.

Maybe you have the same problem somehow, even if you think the scope is tight.

The Doc is out now.

 

[Aries-]

did the bullets that went haywire feel wierd as you pushed them down the barrel ?

if so the sabbot could have "jumped" over the lands and grooves and messed up the plastic cup at the bottom of the sabbot. the sabot should go down smoothly and follow the rifling (tisting down the barrel) instead of jumping over the rifleing. one shop makes a special jag that has a little baring in it so it spins with the bullet.
the guy that made it said he had the same problem. would be doing everything the same then a shot or 2 would be wild.
found that when he got a wild shot. the ramrod shuttered as he pushed the sabbot down the barrel. and figgured out it was juming the rifleing

 

[Picknlittle]

did the bullets that went haywire feel weird as you pushed them down the barrel ?

Not really. It's a pretty firm loader, but consistently so. It's does not require hammering the sabot down, but requires a firm push. If you fire a couple rounds without patching or brushing, it'll make you wish you had before it's seated

I'm still leaning towards moisture because the weird shots are always low. In fact about the same level that a 100 gr load impacts the target.

 

[arcticap]

I think that flyers are sometimes simply due to the nature of sabot shooting, as well as the bullet/sabot/powder charge combination being fired.

Maybe where it is along the bullet flight path that the bullet separates from the sabot is affecting the bullet trajectory and final point of impact.
Sometimes the sabot stays with the bullet all of the way to the target and can be found under the target board, while at other times it will separate sooner and can be found on the ground midway down the range.
Anyway, that's the theory that TC claims is addressed by their "old design" Break-O-Way sabots.
They're probably not the most acurate sabot for every gun, but in some 1 in 48" twist rifles they shoot great.
When it comes to muzzle loading hunting rifles, I don't think that "group size" is as important as having the first shot out of a cold clean barrel be on target.
That's the one that usually counts the most anyway, before the barrel starts to heat up and get fouled. If that first shot won't stay on target reliably, then maybe try another sabot/bullet combination that does.
Also, you really might be pushing the velocity too high with the 150 grain powder charge. If you cut back to say 100 grains on the powder, maybe you'll have less RPM's and destabilizing bullet rotation. And it will be gentler on the riflescope. That's why target velocity ammo & target loads are usually loaded to a lower velocity than high velocity hunting ammo.

 

[Picknlittle]

arcticap, you may be onto something with the sabots affecting flight. A friend has suggested I try a different kind of bullet that used a high pressure cap on the bullet base rather than a full sabot. I've seen his groups,...they're very tight! Consistently under 1.5 inches.

On the powder charge I'll have to say the non-flyers, grouped better with 150 grs of powder. This may change when I change bullets. I'm even considering loose grain Pyrodex or Triple 7 as opposed to the pellets. The pellets seem to slow reloading more than a simple flask with adjustable measure attached. I'm even thinking loose powder may even ignite more uniformly.

The good news is that I have a few months of testing, tweaking and general fun shooting to get it right for deer season. That is after what it all about!

 

[Bezoar]

something i remembered just know. Can you retrieve all of the fired sabots? Examinine them to see that every square inch of it is engaging the rifling. I had a brand of bulk sabots that were made in a way that part of the sabot refused to engage the rifling, possible out of round but I was never sure of that part.
Anyway, that part that never engaged the rifling allowed a bit of gas to escape the barrel before the bullet did, that little puff before the real bang had me screwed up for a while until a friend watching told me what he was seeing.

or could it possible be a paralax issue here? or that famous "scope has to be calibrated for your specific caliber, so dont use a 22 rimfire scope on that 375 magnum.

 

[ccyooper]

How about your ramrod..IS it always returned to the lugs or do you sometimes "forget" to return it to its proper place? Just an idle thought..