Any thoughts on my drop in velocity?

[Jethro21]

Had a good but strange day shooting today and going through my notebook to compare dope, I am thoroughly confused.

I loaded up 75 rounds of my pet load for my Savage, 44.5gr Varget with 178amax. Went out today and my dope was off, way off. My log book showed that in 11/13, I had 5.6 mil for the 730yd target I have. Today, it took 6.1mil to get to my 620yd target. Today my dope was nearly 1 mil more to get to 730yd than last year.

When I reload I use an rcbs scale and hornady digital scale and recheck random bullets throughout the process. Nothing was out of the ordinary.

I have had added bottom metal and had the action bedded, nothing else changed. The Varget is a different lot than last year.

I have never chrono'd this load, but using Shooter to figure today out, it appears I have lost 150fps or so.

Anyone have any thoughts or suggestions?

Tonight I will pull some of my recent loads, reweigh and check against some of my previous loads, but I am scratching my head. I am sure this is a me issue somehow.

On the plus side, the rifle shot lights out today once I figured the correct dope.

 

[KYpatriot]

This probably obvious but did you check your zero? It is the same scope of course right?

150 fps is a lot, I think it would take something crazy unusual for it to really be that much slower, I don't see a different powder lot doing that. Same col, brass, everything?

 

[Jethro21]

I rezeroed on saturday with some of my reloads from a different powder lot, other than that everything is the same. I gotta think I have a hitch in my powder weight somewhere. Got held long in a meeting tonight, will have to pull bullets tomorrow.

thanks for the reply

 

[dauntedfuture]

If you changed lots of Varget then that's the culprit IF you confirmed that your velocity is off. Varget is very inconsistent from lot to lot. If the velocity is the same then its a gun issue.

 

[former naval person]

Re-bedding can change your vibration patterns enough to catch the downswing rather than the up swing. JMHO

 

[Jethro21]

Ok so I just pulled bullets and reweighed charges. I pulled several bullets from my old loads and several from the new loadss I put together sunday night. All of them were within .1gr of my target weight which is 44.5gr (close enough for my equipment and usage).

I am all out of the cans of Varget I used for my previous loadings, so I can't check the lot numbers. I have at this time 3 #1 bottle, 2 of which have the same lot numbers.

So, I guess I will go out and test my older loadings and see what the dope is and compare it to my new loadings. And I guess all over again once I run through my current bottle of Varget.

I try to buy bottles in the same lots, but Varget has been so hard to come by that I just buy it when I see it.

I had initially thought that maybe the temperature had something to do with it, but I have shot this load from 105 to 35 degrees with similar dope and no issues.

So at this time, I am thinking it is lot to lot variations? Again, the other differences with the gun is new bottom metal and an action bedding.

Thanks,
Jethro

 

[CharlieNC]

Blend up all your Varget before reworking the load; then you will at least one larger consistent lot until you get more.

 

[parkervbar88]

ammo temperatures... would be my guess. are you shooting at the same pace? maybe you are shooting quicker that day and the round isnt heating up in the chamber. just a wild ass guess.

possibly cleaning regimes ,copper build up, etc.maybe i think the most likely thing is some wierd batch of powder

 

[supercorndogs]

ammo temperatures... would be my guess. are you shooting at the same pace? maybe you are shooting quicker that day and the round isnt heating up in the chamber. just a wild ass guess.

possibly cleaning regimes ,copper build up, etc.maybe i think the most likely thing is some wierd batch of powder

not with varget but it is very inconsistent lot to lot. velocity drop can also happen because of throat erosion. but i have had to rework up loads when changing lots of varget before. 46 grains over a 168 shot great great velocity changed lots and the bolt handle lift was sticky had to back it off.

 

[Jethro21]

Well, using my Shooter app, inserting my dope from yesterday and comparing from previous range days, my velocity went from 2650 to 2500. I am not caught up on speed, just consistancy. I guess I will pull the ammo I just loaded, blend the lots I have and work it up again. I do have about 200 rounds of my previous loads I will shoot up.

So now I got to ask, what temp stable powder have people found has little lot to lot variation? I am gonna have to go that route in the long run I think.

thanks,
Jethro

 

[Aimsmall55]

Well, using my Shooter app, inserting my dope from yesterday and comparing from previous range days, my velocity went from 2650 to 2500. I am not caught up on speed, just consistancy. I guess I will pull the ammo I just loaded, blend the lots I have and work it up again. I do have about 200 rounds of my previous loads I will shoot up.

So now I got to ask, what temp stable powder have people found has little lot to lot variation? I am gonna have to go that route in the long run I think.

thanks,
Jethro

Figure that one out ..... Please let me know!

 

[TheBelgian]

I was gonna say the same!!! Varget is known for being inconsistent and maybe your powder is a bit humid? Can you chronograph your loads?