.54 POI

[mainiac]

Started shooting my new .54 beck, and am getting to learn how it shoots.Have a question,,,,using fff goex,,with the current sights,80-85 grs shoots to center,,100 grs,shoots 3 inches high,,and 60 grs,shoots 3 inches low,all @50 yards.

Does this 6 inches of vertical sound unusual,in a .54,with the difference of 40 grs of powder??

I have .32,.36,40,and 50,s but they dont seem to be this extreme as far as powder charge.

BTW,barrell is a colerain, and between 85,and 90 grs, it will shoot 5 shot groups,under an inch!!!SWEET!!

[wvmtnman]

Though I don't have the shooting experience of others here, that sounds about right.  I have shot similar loads in my .54 and have had the same results.  If you are going to deer hunt with it, you may want to work up a 100 yard load.  I wouldn't go too much over 100 gr of 3f,  I personally feel that is close the max.
                                                                             Brian
                                                                       

[hanshi]

As a general rule, increasing powder charge results in rising point of impact.  This is not always so but is usually what happens in my shooting.  Example: my .45 Lancaster hits an inch or so high at 50 yards with 70grns of 3f.  but with 40 grns of 3f it hits 2" low at 50 and just a shade low at 25.  I've never run into the reverse of this happening.

[Rasch Chronicles]

Sir,

I believe that you may be seeing the effects of what is called "barrel timing." As projectile weights go up, the ammount of time they spend in the barrel change, the same happens as powder charges change. I do not know the details, but if memory serves correctly, the higher the projectile weight, the longer it stays in the rifle, the more time the rifle can recoil, and the point of impact goes higher.

I think...

 Best regards,
Albert  Rasch
The Rasch Outdoor Chronicles

[BrownBear]

I'm assuming that your Beck has low sights.  That would minimize another factor in your relative POI's- height of sights above the bore.  

[Daryl]

Started shooting my new .54 beck, and am getting to learn how it shoots.Have a question,,,,using fff goex,,with the current sights,80-85 grs shoots to center,,100 grs,shoots 3 inches high,,and 60 grs,shoots 3 inches low,all @50 yards.

Does this 6 inches of vertical sound unusual,in a .54,with the difference of 40 grs of powder??

I have .32,.36,40,and 50,s but they dont seem to be this extreme as far as powder charge.

BTW,barrell is a colerain, and between 85,and 90 grs, it will shoot 5 shot groups,under an inch!!!SWEET!!

Is that 5 shot grouping at 25 yards, maniac?

High sights will easily give the differences in elevation you note. Usually, lower sights don't cause that much of a rise, as Brown Bear noted. a 6" spread seems a bit much - but - will make targets and game shooting with one set of sights easy. ie: 80gr. for target shooting as it will be about zero'd at 25 & 50 yards, and 100gr. for hunting as it shold be zero'd about 110yards- without moving the sights.

I have one rifle only, that shoots lower with increased powder charges. It did this when it was 42", and mounted on a longrifle. It still does this when cut to 36" and is now mounted on a 1/2 stock rifle - still shoots lower with increased powder charges.  Barrel harmonics don't seem to be the determining factor with this gun - as the harmonics must be different going from 3 pins and full stock to a single barrel wedge and very short, 1/2 stock. Of course, that's merely a guess.

[mainiac]

50 yard daryl...this may turn out to be my most accurate barrell,ever. shoots real good,and i havent played with the loads hardely at all.

My rear sight is pretty low,and i had to buy the tallest front sight that track sells.The front must be .500 tall. Even with this tall front sight,it really should be a little taller,cause the way it is,it is dead center with 80 grs,but 3 inches high with 100.

Im kinda thinking the barrell has a upward bend to it,or it was bored off center,,,whatever is going on with it,is really a moot point,cause it shoots so good,i can forgive her!

[Daryl]

Sounds like a 100gr. hunting load and a normal target load of 80gr. to me - without sight changes.

[Don Getz]

Something bothers me here.   If the gun will shoot l" groups all day with 85-90 grains of powder, why would you want to
change anything?   Why not stick with an accurate load.   Sight it in to hit about an inch high at 50 yards, it should only
be about 2 to 3 inches low at 100.  If you can't hit a deer, or a bullseye with that combination, it's not the gun or load........
Don

[Standing Bear]

Im kinda thinking the barrell has a upward bend to it,or it was bored off center,,,whatever is going on with it,is really a moot point,cause it shoots so good,i can forgive her!

Barrel run out.  That is why the barrel manufacturer's name, if there is one, is on one flat and the barrel is usually breeched so that flat is on the bottom.  If the run out was horizontal you could be shooting 3" left at one distance and 3" further left at another.  Glad this one was breeched correctly.

As you have learned, barrel shoots good and the problem is handled with load and sights.  Keep on shootin'.

TC

[mainiac]

Something bothers me here.   If the gun will shoot l" groups all day with 85-90 grains of powder, why would you want to
change anything?   Why not stick with an accurate load.   Sight it in to hit about an inch high at 50 yards, it should only
be about 2 to 3 inches low at 100.  If you can't hit a deer, or a bullseye with that combination, it's not the gun or load........
Don

didnt say a thing about changing anything. Just wondering about the vertical extreme between light and heavy loads.

[SCLoyalist]

A 6 inch spread vertically at a range of 50 yards is too much to be explained by a difference in muzzle velocity for the powder charges you mentioned.   The 'barrel timing' theory mentioned previously is a possible explanation.

If you have a 42" barrel, you should be getting somewhere around 1425 fps from 60 gr,  1625 fps from 80 gr, 1740 fps from 100 gr.  If the 80 gr hits at point of aim at 50 yds,  dropping to  60 gr/1425 fps would lower point of impact by 1/2", raising to 100 gr/1740 would raise point of impact by 0.3".   For a 3 to 6 inch spread, something else is at play.  If you have a shorter barrel than 42", all the muzzle velocities would drop a couple of hundred fps, and give more spread, but not 3" worth of spread.

An interesting experiment might be to let someone else shoot the gun, or shoot it off a rest, and see if or how the results change.  Better yet, chronograph to see what the actual muzzle velocities are so you could plug the numbers into a ballistics program and see the bullet path.   

[Daryl]

1/2" and .3" measurements do not take into consideration the height of the sights nor the recoil induced elevation which can be attributed to stock design, and shooter configuration as well.  There isn't a simple mathematical explanation for the elevation change.  Granted - 6" from 60gr. to 100gr. is a lot - but 3" could be totally normal. Considering there is approximately 3 "error" - something else is effecting or governing the elevation.

Personally speaking, having an accuracy load of 80 to 90gr. of 3f in a .54, with an additional 3" elevation with a change form 80 to 100gr.- I'd have a farily flat shooting load of 80gr. for trail walks and then go hunting with 100gr. and not have to change the sights.  That extra 3" of elevation at 50 yards, would give me a zero at around 110yards, maybe 115yards, which would give me a point blank on a whitetail of decent size to about 130yards - GREAT! I'd even try 110gr. of 3f to see what would happen.

[hanshi]

Sir,

I believe that you may be seeing the effects of what is called "barrel timing." As projectile weights go up, the ammount of time they spend in the barrel change, the same happens as powder charges change. I do not know the details, but if memory serves correctly, the higher the projectile weight, the longer it stays in the rifle, the more time the rifle can recoil, and the point of impact goes higher.

I think...

 Best regards,

Adding to that I've noticed the shooter can have a major affect on poi, too.  I was shooting a gun at the range which was consistently hitting high.  Another shooter fired my gun and it hit dead on for him.  I would guess we each hold a gun differently and that, too, can make a difference.
Albert  Rasch
The Rasch Outdoor Chronicles