Barrel Harmonics

[GarethMarijt]

I apologise in advance if this is a silly question.

After conducting a ladder test at 300 yards, you find an optimum load range for your rifle and from this you have a range of velocities. If you decide at a later date to change your powder/bullet combination, could you just load up to the same velocities and not perform the ladder test?

I guess what I am asking is, does the "sweet spot" once you have found it, apply to any combination of bullet/powder that matches the pre-found optimum?

Thanks in advance
Gareth

 

[bheadboy]

From my experience, it is a starting point, however,different burning rates cause a different pressure curve and thus different harmonics, so seldom have i found powders of dissimular burning rates to act the same,

often in the slower powders i have found 4350/4831/rl19 to act work reasonably well in this regard
on faster powders if find 2015/h322 etc. do

on mid varget/4064/ simular.

Bob

 

[alf]

When I first switched over to the 30x47 in my Hunter gun (from a 308), I tried three different powders with a 135 Chism. All three came into their accuracy node at 2925. More often than not, this isn't going to happen.

For hunting guns, I have chronographed a new powder lot to compare to an older lot, and adjust accordingly, but didn't achieve the same accuracy.

So, to be safe, I'd say that every time you change one component, you need to go back to square one.

 

[GarethMarijt]

Gents, thanks for your replies,

I guess I had hoped that it would be ok (within reason) to change the bullet/powder combination within the velocities, then fine tune afterwards.

Being in this part of the UK, I have easiest access to SMKs and Vit powders, but opportunities for ladder testing are rare and difficult.

Gareth

 

[artbosco]

Does the "sweet spot" once you have found it, apply to any combination of bullet/powder that matches the pre-found optimum?

I've found that by just changing the manufacturing lot of the same powder, leaving everything else exactly the same, can change barrel harmonics. It may get you into the ballpark, but you do need to refine the tune.

 

[sailhertoo]

Does the "sweet spot" once you have found it, apply to any combination of bullet/powder that matches the pre-found optimum?

I've found that by just changing the manufacturing lot of the same powder, leaving everything else exactly the same, can change barrel harmonics. It may get you into the ballpark, but you do need to refine the tune.

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