help!!!! deviation in fps. I need advice

[tobacco road]

I'm going crazy!!!! I have a 6.5 stw shooting 123 Hornady a max
215 federal primers, weight sorted brass "rem" flash hole de burr, retumbo powder. I am using a balance beam scale. And a cald well chrony. Keep getting up too 100 fps deviation I normally shoot 140 berger vld with only about 20 fps +or- I changed loads for coyote hunting and I cannot get a consistent median for this round, is there something I'm forgetting? Any input would be great. I cannot zero my scope with that much inconsistent fps or make accurate drop data. I'm sure this a hot topic, but I cannot get it to change, what do yall think???

 

[pyroducksx3]

I say run your bergers for everything. I run berger 180 gr in 7 mag mag for everything rocks, coyote, steel, deer or elk they all get the same bad medicine. I like practicing what I hunt with just gives me confidence

 

[MudRunner2005]

I say run your bergers for everything. I run berger 180 gr in 7 mag mag for everything rocks, coyote, steel, deer or elk they all get the same bad medicine. I like practicing what I hunt with just gives me confidence

I agree. I do the same thing.

 

[tobacco road]

That's what I was thinking just stick to what works, but I was trying to save my berger bullets for hunting. I figured i would use the amaxes for coyotes. But I think you guys are right just stick with what works good practice anyways

 

[Wedgy]

Are you are sure it's not the chrono ? They are very finicky when it comes to light and muzzle blast among other things. I finally picked up a Magneto speed so I don't have to mess with all the headaches of a typical chrono unless I want to shoot my bow.

 

[tobacco road]

No I'm not 100% sure the chrony is accurate. It's always in the back of my mind, I 2 as shooting 11 ft from the chrony, is that still to close? Plus I have a muzzle brake

 

[BergerBoy]

I have found that some loads/powders just are not as efficient as others.

Example: My usual H1000 load gives me ~ 12 fps ES. H1000 has been somewhat hard to find (for me) and I came across Retumbo. It is close in burn speed and using the same brass, primers and bullets I has an ES of 38 fps. I double weigh it etc...
Retumbo is great powder but for some reason H1000 burns/preforms better in my 300.
Even OAL can through off your fps.

 

[tobacco road]

Are you are sure it's not the chrono ? They are very finicky when it comes to light and muzzle blast among other things. I finally picked up a Magneto speed so I don't have to mess with all the headaches of a typical chrono unless I want to shoot my bow.

Is it worth the money??? Just looked it up. There definitely proud of it.

 

[FearNoWind]

Is it worth the money??? Just looked it up. There definitely proud of it.

IMO, it's worth the money. It removes all doubt when I'm working up loads - when the unexpected happens my MagnetoSpeed isn't even a consideration in my mind. If I can remember to plug the connector into the receiver "all the way" it works a lot better cuz that's the switch to turn it on. Doggone it, I do get careless sometimes.
I have never used a chrono that I felt came anywhere close to the MagnetoSpeed for performance reliability.
Oh; No - I aint' a stock holder.

 

[Trever]

I'm am having the same problem with varget in my 308. 99 fps ES. I don't get it. Case capacity was 53.5 with no more than .5 SD. Will be stepping the load up, velocity was pretty low for a 28 in tube.

 

[tobacco road]

Thanks for the advice man, I see purchasing one in the near future

 

[WildRose]

I'm going crazy!!!! I have a 6.5 stw shooting 123 Hornady a max
215 federal primers, weight sorted brass "rem" flash hole de burr, retumbo powder. I am using a balance beam scale. And a cald well chrony. Keep getting up too 100 fps deviation I normally shoot 140 berger vld with only about 20 fps +or- I changed loads for coyote hunting and I cannot get a consistent median for this round, is there something I'm forgetting? Any input would be great. I cannot zero my scope with that much inconsistent fps or make accurate drop data. I'm sure this a hot topic, but I cannot get it to change, what do yall think???

Too light of a bullet for that much case capacity but that's probably not what's causing your deviations.

Neck tension could be another possibility. I'd check to see if your neck thickness is consistent and be sure they are trimmed to proper length. If some of he necks seem to be thicker or thinner that could definitely be your problem.

My guess would be inconsistent powder measure or your chrony could easily be off quite a bit.

Run your dope with what you have now and shoot some 300 and 500yds groups and compare them to your dope and see how tight the groups are.

If they are tight, you don't have that much deviation in velocity.

When you compare your actual drops vs your charted drops adjust your velocity in the calculator to see if you can get them to match up.

 

[BergerBoy]

IMO, it's worth the money. It removes all doubt when I'm working up loads - when the unexpected happens my MagnetoSpeed isn't even a consideration in my mind. If I can remember to plug the connector into the receiver "all the way" it works a lot better cuz that's the switch to turn it on. Doggone it, I do get careless sometimes.
I have never used a chrono that I felt came anywhere close to the MagnetoSpeed for performance reliability.
Oh; No - I aint' a stock holder.

I have to agree strongly.

 

[cowboy]

Thanks for the advice man, I see purchasing one in the near future

If the budget is a little tight after the holiday season and tax day coming up just do what we did before all the modern innovations became available. Load up some and shoot them at some distance and see what kind of vertical spread you get in real life. If you get satisfactory vertical spread than it does point to your current chrony - but who cares what a chrony says if real life says different.

I have a light sensitive chrony and a magnetospeed. I've used them simultaneously and individually many times and still to this day will never use the data of either one over actual field testing.

The Magnetospeed may get you to your end results a little faster but real life bullet holes in a target will always be your best results.