168 SMK over IMR-4064 ladder...

Asking for suggestions reading this ladder test.

Stevens 200 action 308 Win with X-Caliber 26" SS Varmit 10 twist barrel in a Sharp Shooter Supply LVT stock.

Most specs on the load are on the picture and test was shot round robin style from 40 gr to 45.5 gr. I see the node at shots (5,7,9) which would be from 41-42 grains but I don't really see a node up high. I went .5 grain past max charge on this test. Just a note, 168 FGMM runs about 2760 FPS out of this barrel.

I will probably shoot my next ladder in order. I shot them round robin style because that is how I did it with my sporter barrel. However, with a varmit contour heat is not as much an issue in a small run like this one.. Excuse the confusion of the round robin format...

Thanks for any suggestions.

I edited the photo to show them in order for ease of understanding...

http://i185.photobucket.com/albums/x...ps612ca8d0.jpg

For what it's worth the military long range round M118LR is 41.7gr IMR 4064 with the 175gr Sierra Match bullet. This load worked well in both my M1A1 and bolt action Savage 308.
M852 used 42gr IMR4895 under the 168gr Sierra Match bullet.

You have a node at 1/2, another at 3/4/5, and a third at 7/8. Adding in your chrono numbers I would work with the 7/8 node HOWEVER, first you need to load up 12 more rounds just like those and try to duplicate your results. Unless you know your rifle is capable of sub 1" groups at 300 yards you may just be looking at compensating errors. Even so that is a very good ladder test.

In doing some more studying on this test, I can't understand why there is over a 9" spread from 2450 FPS to 2800 FPS.. According to the baliistic calculator that I use (Strelok) there should be just over 5" of difference in drop.

I zero'd the rifle with 168 FGMM prior to this test with a .504" 3 shot group then dialed up 4.5 MOA so I'd be somewhat close on the 300 yard shot...

Something changed in that picture from the first time I looked at the post.

I rearranged the numbering such that it would be in order of charge weight and be easier to analyze...

yes the load weight was not in the correct order so nothing made sense. It looks much better now.

like JTCrl said you have a node at 7/8 but need to test it...also if looking for more velocity it looks to me like you had another one coming in at 11/12...the sierra manual shows 43.4 as max with a 26" barrel and a fed210 primer so you are above max but if your not seeing any pressure signs you may want to try going up a little in .2g increments but keep in mind your working up a load at 55degs and in the summer it may be a problem with the same load...personally id work with the 7/8 load until its hot and then if you want more work with it then...i have two loads worked up for both of my riffles 1 for summer and one for winter as the temps are 60degs different from summer to winter here. also might want to try some imr 8208xbr...lotta guys shooting that in matches here in the 308s.

Quote:

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Originally Posted by wbm

For what it's worth the military long range round M118LR is 41.7gr IMR 4064 with the 175gr Sierra Match bullet. This load worked well in both my M1A1 and bolt action Savage 308.
M852 used 42gr IMR4895 under the 168gr Sierra Match bullet.

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spot on.
I found my sweet spot with 41.5grs of 4064 and 175,s out of my 10 FCP-K.

Quote:

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Originally Posted by cowtownup

Asking for suggestions reading this ladder test.

Stevens 200 action 308 Win with X-Caliber 26" SS Varmit 10 twist barrel in a Sharp Shooter Supply LVT stock.

Most specs on the load are on the picture and test was shot round robin style from 40 gr to 45.5 gr. I see the node at shots (5,7,9) which would be from 41-42 grains but I don't really see a node up high. I went .5 grain past max charge on this test. Just a note, 168 FGMM runs about 2760 FPS out of this barrel.

I will probably shoot my next ladder in order. I shot them round robin style because that is how I did it with my sporter barrel. However, with a varmit contour heat is not as much an issue in a small run like this one.. Excuse the confusion of the round robin format...

Thanks for any suggestions.

I edited the photo to show them in order for ease of understanding...

http://i185.photobucket.com/albums/x...ps612ca8d0.jpg

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what elevation are you at?

The spead variation you see is also due in part to the barrel harmonics, whipping/vibration of the barrel up and down as the bullet passes through it. Depending on when the bullet exits in the vibration pattern greatly influences the point of impact. You want to be at the top or bottom of the wave. Pick up a copy of Harold Vonn's Rifle Accuracy Facts and it explains this in great detail.

You can see these patterns by plotting the muzzle velocity versus the corrected bullet impact point (add in the calculated bullet drop due to gravity using a ballistics calculator and your muzzle velocity). It should look like a sine wave. Mine have always seem to have an up slope to them. You can spend more time than it is worth playing with this. I would prefer this latter again, this time with 0.3 gr increments and see if it repeats.

Luck, Tim