Varget & Sierra 77gr Low Velocity

[slitzer]

I'm trying to find my sweetspot and I have ran Dan's OCW starting at 23.0 gr to 24.0. with a sierra 77gr Matchking w/cannulure & light LFC crimp
Deal is at 23.0gr I'm getting Max Spread (CTC) of 0.282 MOA 3 shots. with a average FPS of 2429 (I would say my sweetspot)
Anything else going up the chain by .2 the group starts opening up I have not tried below 23.0gr yet because of the velocity's.
This is a 18" Krieger Barrel by Compass lake. New Lapua Brass & Rem 7-1/2 Primers. C.O.L of 2.260"
Quickload tells me I should be getting 2616 FPS at 23.0gr but I have not done my case capacity overflow yet. and it tell me this is a near max load. (they was no pressure signs all the way up to 24.0gr)
I'm just a little concerned at my low velocity. Should I go above 24.0gr and watch very carefully my pressure signs. and look for another sweetspot. I have read some peoples load is around 25.4gr of varget.
I will use this round for target, rabbit, squirrel, hog & anything else that moves.
I don't want to invest in a hunting round since I have a lot these.

Sierra says 24.0gr is max. 23.0gr should get me 2650fps http://www.sierrabullets.com/index.cfm?s...issue=3#loaddta
Hodgton says 23.7C is max with 2737fps
And of course I have used the minus 20fps per inch loss of velocity, reduced from test barrels.
now that I'm all out of breath, I'm all ears guys, any help will be appreciated.

 

[jmtyndall]

Re: Varget & Sierra 77gr Low Velocity

Powder he's using is Varget for those a bit confused. At least, that load data matches what I have for Varget and that bullet.

Don't forget temps can affect velocity and pressure.

No pressure signs at 40* doesn't mean it's safe at 100*

 

[MitchAlsup]

Re: Varget & Sierra 77gr Low Velocity

A) you forgot to tell use about the length of the barrel, manufacture (or factory), how many shots through the barrel,... Nor did you mention the name of the Chronograph, or how new the batteries were, or the sky conditions under which shooting took place.

B) Then we need reloading recipie: Cases, primers, seating depth, OAL,...

C) It appears you are tryinig to dial in a long range load (also not specified--as opposed to a benchrest load, for example).

For a long range load, the first thing you need to do is to find the point where pressure signs appear. You do not (need to) shoot groups while doing this. You shoot a round, examine the case for pressure signs, then load the next higher charge weight and repeat. When yo find the first pressure sign you stop.

Then you drop back 5% (min) and search upwards for the accuracy node just under pressure signs with 1% increments in charge weight. Here, it is recommended to use 5-shot groups--expecially if you have an accurate gun. This is where OCW is followed.

Once you find one or more accurate nodes, you need to survey the charge weight range around the accurate group to see how wide the window of great accuracy is.

Once you find this accuracy window, you are ready to begin bullet seating (and crimp in your case) experiments.

 

[REELDOC]

Re: Varget & Sierra 77gr Low Velocity

24.5 grains Varget or RE15 with Sierra 77 or Hornady 75 is a good load.

 

[M25BeastShooter]

Re: Varget & Sierra 77gr Low Velocity

24.5gr Varget with a 69 Sierra, 77gr Sierra or 75gr A-Max (the 75 A-Max loaded long for 600) all work great for Service Rifle

 

[Grump]

Re: Varget & Sierra 77gr Low Velocity

Can't tell much without fired case capacity, WITH the length base to case mouth.

I found Varget to run SLOW with that bullet, out of a Gen-you-ine Colt 1:7 HBAR, 20-inch barrel. Been a few years ago.

 

[slitzer]

Re: Varget & Sierra 77gr Low Velocity

Hello Guys thanks for the help
okay I've got a average(x5) case capacity overflow of 30.68 measured with water flat with top of case. That brings my velocity's more in line with real world, with quickload. I'm using chrony beta master on a sunny day with screens and new battery
I have a case length of 1.750" temp that day was about 70.
I have less than 100 rounds through this 18" barrel.
I will be shooting anywhere from 50yds to 600yds so yes kinda of a long range round. I am also sorting cases and bullets. for the longer range shots and for development of this load.
I am just wanting a little more punch at the longer ranges.
<span style="text-decoration: underline">I think I will try going up in charge weight and watch for my pressure signs. regardless of quickload's output. </span>as others have suggested


Cartridge : .223 Rem. (SAAMI)
Bullet : .224, 77, Sierra C-HPBT MatchK 1478
Cartridge O.A.L. L6: 2.260 inch or 57.40 mm
Barrel Length : 18.0 inch or 457.2 mm
Powder : Hodgdon VARGET

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 84 19.60 2150 790 30042 7619 85.1 1.253
-18.0 86 20.09 2203 830 32011 7881 86.4 1.219
-16.0 88 20.58 2256 870 34109 8139 87.7 1.185
-14.0 90 21.07 2309 912 36345 8392 88.9 1.153
-12.0 92 21.56 2363 954 38731 8640 90.0 1.119
-10.0 94 22.05 2416 998 41275 8881 91.2 1.087
-08.0 97 22.54 2470 1043 43988 9116 92.2 1.055
-06.0 99 23.03 2524 1089 46899 9342 93.2 1.025 ! Near Maximum !
-04.0 101 23.52 2578 1136 49990 9560 94.2 0.995 ! Near Maximum !
-02.0 103 24.01 2632 1184 53273 9768 95.0 0.967 ! Near Maximum !
+00.0 105 24.50 2686 1234 56783 9966 95.8 0.939 !DANGEROUS LOAD-DO NOT USE!
+02.0 107 24.99 2740 1284 60540 10152 96.6 0.913 !DANGEROUS LOAD-DO NOT USE!
+04.0 109 25.48 2794 1335 64568 10327 97.3 0.887 !DANGEROUS LOAD-DO NOT USE!
+06.0 111 25.97 2848 1387 68889 10489 97.9 0.862 !DANGEROUS LOAD-DO NOT USE!
+08.0 113 26.46 2903 1441 73532 10636 98.4 0.838 !DANGEROUS LOAD-DO NOT USE!
+10.0 115 26.95 2957 1495 78528 10770 98.9 0.815 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 105 24.50 2816 1356 66913 10045 99.4 0.875 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 105 24.50 2521 1086 46932 9465 88.9 1.022 ! Near Maximum !

 

[Saito]

Re: Varget & Sierra 77gr Low Velocity

I wouldn't crimp the Match Kings at all, thin jacket doesn't react well to a crimp in my experience.

 

[35WLN]

Re: Varget & Sierra 77gr Low Velocity

I second the don't crimp em. I just made sure there wasn't a rough edge and called it good and my groups came in a little.

 

[slitzer]

Re: Varget & Sierra 77gr Low Velocity

Slight Light Crimp because their Cannelure Type


Okay went back out and did a pressure test 24.0, 24.1, 24.2, 24.3, 24.4 & 24.5 (looks good no pressure signs)
proceeded to load 3 of each and run groups.

Looky what I found at 24.3

when complete, I loaded 10 rounds with a average velocity of <span style="text-decoration: underline">2591*fps</span> and a SD of 21.08
I shot 2 sets of 5 at different targets with the largest CTC being less than 3/4" it was getting dark, and I didn't feel like I was shooting the best I could. I will follow up some more. "Starting to love this Krieger Barrel"

"There it was sitting right above what every book and online resource including Quickload, said was a dangerous load."
I had no pressure signs at 24.5 and I probably could have went more, But I'm cool with these results.

 

[M25BeastShooter]

Re: Varget & Sierra 77gr Low Velocity

I use a Dillon Taper crimp on my Service Rifle loads as the rapid fire stages 2 in first mag and 8 in second. But just a light one as I don't want to deform the jacket

 

[rick2800]

Re: Varget & Sierra 77gr Low Velocity

amazing the difference of .1 grain isnt it ? i tend to listen to quickload and the books also guess i need to go back to the way i use to do it (look for pressure then back down).

 

[35WLN]

Re: Varget & Sierra 77gr Low Velocity

Looks pretty good, now what does a 10 round group look like at 100, 200 & 300?

 

[MitchAlsup]

Re: Varget & Sierra 77gr Low Velocity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: slitzer</div><div class="ubbcode-body">Looky what I found at 24.3</div></div>

Nice group. Now go back and make 25 rounds and shoot 5 targets with 5-shots each and see if it stays that small. Then you will have ruled out flukes.

 

[leadbullet]

Re: Varget & Sierra 77gr Low Velocity

I am using 24.5 varget with the same bullet in LC brass with no issues at all and it is good to 600yds in my service rifle.

 

[gau17]

Re: Varget & Sierra 77gr Low Velocity

I'm using 25.0 Varget seated mag length with Rem 7 1/2 primers & LC brass. getting close to just shy of 2700 fps.

18" Douglas barrel w/ 1:8 twist.