308 win. Varget results

[Nicholas]

I finally tested my first handloads today. Thank you all for your help and advice.

I started with 43 grains of varget and worked up in .2 increments to 45 grains, firing 3 shots each increment. Fed 210M, 175 Sierra matchkings, Lapua brass. Temperature was 95 degrees in the shade, elevation was 5500 ft above sea level. All testing was done with my SR90 with 24 inch schnieder match barrel.

I had several three shot strings with two shots very close together in velocity but one would always be off a lot, what gives?

Chronographed them with my Oehler 35P, chronograph was set seven feet from the muzzle.

I thought my results would be of interest to you guys.

Velocity_________Grains____Mean_____Extreme Spread
2665-01-2670_____43.0______2650_____23
2644-02-2649
2642-03-2646

2658-04-2663_____43.2______2655_____8
2657-05-2660
2650-06-2653

2658-07-2661_____43.4______2672_____31
2689-08-2692
2669-09-2672

2658-10-2664_____43.6______2670_____31
2689-11-2695
2662-12-2667

2693-13-2699_____43.8______2695_____8
2693-14-2698
2701-15-2706

2722-16-2728_____44.0______2708_____28
2694-17-2699
2710-18-2716

2676-19-2681_____44.2______2696_____32
2708-20-2713
2705-21-2710

2717-22-2722_____44.4______2708_____15
2707-23-2711
2702-24-2707

2722-25-2728_____44.6______2723_____2
2722-26-2727
2724-27-2730

2745-28-2752_____44.8______2738_____20
2725-29-2733
2744-30-2752

2751-31-2757_____45.0______2764_____20
2769-32-2775
2771-33-2775

Primers started to crater at 45 grains so I stopped there. Besides the velocity was already more than I wanted.

I haven't shot for several months and the size of the groups reflected that. I was mostly concerned with velocity than accuracy during this test. I had several groups with two shots in one hole but the third would be a half inch away.

From a velocity stand point only what point (in grains) looks the most promising?

I plan on doing my accuracy testing at 300 yards.

[ 06-30-2002: Message edited by: sr90 ]

 

[Brent]

I have always found accuracy to be around 2500 to 2600 with 180's, 165 and 8's. I have not shot the 175, but for my guns I would look in the 2550 to 2650 range.

I would fire loads in this range at one target with one round at each load in two tenth grain increments while plotting on a paper each hit and velocity.

You will see a sweet spot emerge where all rounds stay tight in a certain charge range. Everything outside this range will be all over in comparison.

From there just pick the middle charge weight in this range and a forgiving load is found.

Another bullet will likely shoot better rather than another powder if not satisfied at that point, I've been told. Pick your powder and find your bullet so to speak.

If you cannot find a good load with a couple good bullets like this right away you probably need a new barrel is said.

Also, clean first then foul the barrel with that powder being tested for 3 to 5 rounds before starting.

Development test would be done at 200yds, 300 if no wind was present.

In your first test, cases firing rounds #1,8,11,16,19,22,29 and 31 are suspect and would be marked and set aside for later checking of case capacity due to the velocity variation within the load fired and use the other cases for the next test.

The one you mention that was always "off" could likely be resolved here too.

I've heard that CCI BR2 primers solved many flier issues for quite a few people on another site. I switched to them from the GM210M's the last brick I bought but can't say yet if they changed because I haven't hot a known load with them yet.

Good luck.
Sorry about the long post.

It sounds like yours will be a real shooter with very little effort though.

 

[milanuk]

Quite a few people seem to find the 175gr SMK/45.0gr Varget/Winchester cases/CCI BR2 primers to be the 'cats meow' when it comes to a good load for the .308 Win. I've heard of a few people whose guns showed some excessive pressure @ 45.0 gr; usually backing down to 44.5-44.6gr seems to result in acceptable performance and still good accuracy.

From my gun (factory Rem 700VS w/ 26" pipe) this load nets about 2750 fps, and low ES/SD (sorry, don't have the numbers anymore. I ran up as high as 46.0 gr, but didn't see enough velocity increase to warrant burning the extra powder. As far as I know, there are more than a few people out there getting 2700fps+ from this load (45.0gr) w/ no problems.

Monte

 

[Nicholas]

I have a BDC on my scope for the 175 grain matchking going at 2680 fps, so I didn't really want to go over 45 grains because I didn't need the extra velocity.

Brent

Thanks for the tip on finding the center of the group, I will be watching for it. At the higher charges the POI was getting really high and to the left, some of the groups were over an inch, so I could tell the bullet was exiting the muzzle at the wrong point of the barrels harmonics.

I will also try shooting a lower charge, probably from 42-43 next time.

 

[Nicholas]

Brent

How is the best way to measure the case capacity?

"firing rounds #1,8,11,16,19,22,29 and 31 are suspect" are there usually this many cases that have variations in case capacity??

I think you are right on the money as the groups that had two shots in one hole and one flyer were within the strings you mentioned.