.308Win Reloading Delima - Help

[Rharris]

Well, just when I thought I was headed down the right road. Here's the problem - I have been working up 100 yard loads for .308 and settled on Sierra 168gr MK, 43gr Varget, CCI 200 with a .005" jump. These rounds have produced groups of .207" & .250". I wanted to begin same on 300+ yard work up and started with the following - Sierra 175gr., 43gr Varget and a .005" jump. Keeping the jump the constant I began bumping up powder at .3 per 5 shot group. My first 5 shot group at 300yds was crazy wild - maybe 5-6" and the second group was about same. Nothing was even close to a group - holes scattered all over paper. At this point I don't know what to correct next! Should I keep powder at 43gr and start varying the jump .010" - .020"? Very strange - never had such a variance before. The loads were as good as I can make them - Powder throw no more than .1gr var / runout was no more than .002". SD was 9fps and ES was 19. Anybody have any ideas about what I should do next? Thanks in advance for your help.

 

[Twitchy]

Well, just when I thought I was headed down the right road. Here's the problem - I have been working up 100 yard loads for .308 and settled on Sierra 168gr MK, 43gr Varget, CCI 200 with a .005" jump. These rounds have produced groups of .207" & .250". I wanted to begin same on 300+ yard work up and started with the following - Sierra 175gr., 43gr Varget and a .005" jump. Keeping the jump the constant I began bumping up powder at .3 per 5 shot group. My first 5 shot group at 300yds was crazy wild - maybe 5-6" and the second group was about same. Nothing was even close to a group - holes scattered all over paper. At this point I don't know what to correct next! Should I keep powder at 43gr and start varying the jump .010" - .020"? Very strange - never had such a variance before. The loads were as good as I can make them - Powder throw no more than .1gr var / runout was no more than .002". SD was 9fps and ES was 19. Anybody have any ideas about what I should do next? Thanks in advance for your help.

Try loading closer to mag length (2.8ish). That charge range/bullet combo is hard to go wrong with. The variable you changed from the typically good load is the load length. SMKs don't mind jump.

What's your barrel length/velocity?


How did the 168s group at 300?

 

[BoydAllen]

You need to back up and do a complete load workup at 100 with the 175s. Hold the seating depth constant and do a full range charge weight evaluation, shot over flags. Once you have your charge weight, you can play with seating depth. Assuming that you are able to make it work at 100, only then take it out to 200 and then 300.

 

[NC308]

What is the farthest you will be shooting? If not over 600 or so just stay with the 168 since it is shooting good.

But if you want the 175 then start say .010 jump and load from 43 grs up to your guns max in .2 gr increments. I'd say there is a node around 43.5 and just north of 44gr.

 

[Rharris]

Try loading closer to mag length (2.8ish). That charge range/bullet combo is hard to go wrong with. The variable you changed from the typically good load is the load length. SMKs don't mind jump.

What's your barrel length/velocity?


How did the 168s group at 300?

Ruger RPR 20" barrel / Twist 1-10" - Ave Vel - 2580fps.
I wish I had taken some 168's with me to use as a standard - will next trip. I have read a number of threads with that bullet having .015 - .020" jump - that's why I was surprised at 100 yards it performed so well. As I when out further (w/ 168) the groups started spreading. Realizing the 175gr was going to behave different, but didn't expect what happened. Thanks!

 

[Rharris]

You need to back up and do a complete load workup at 100 with the 175s. Hold the seating depth constant and do a full range charge weight evaluation, shot over flags. Once you have your charge weight, you can play with seating depth. Assuming that you are able to make it work at 100, only then take it out to 200 and then 300.

Good advice! Thank you

 

[Rharris]

What is the farthest you will be shooting? If not over 600 or so just stay with the 168 since it is shooting good.

But if you want the 175 then start say .010 jump and load from 43 grs up to your guns max in .2 gr increments. I'd say there is a node around 43.5 and just north of 44gr.

Josh, I think I will start there and see how the 168's do at 300 - 400 - 600. Question: If things begin to spread would you hold powder constant and increase jump or vice versa? Thanks!

 

[expiper]

op,,,shoot a few of the proven loads again and see if they still work well,,,maby your scope went bad or bedding ,,,check action screws,,,etc,,,,Roger

 

['Freak]

The 43 grains of Varget what works so well for the 168 gr. SMK is a half grain under the listed maximum charge weight shown in Sierra’s latest manual. That same 43 grains when behind the heavier 175 gr. SMK is 1.3 grains over the listed maximum charge weight and so may well be ‘too hot’ for the heavier bullet. Back down on the charge weight to ‘bout the middle of Sierra’s listings for the 175 gr.SMK. Begin at maybe 38 or 38.3 grains of Varget and work your way back up again, increasing the charge weight using 0.3 grain increments.

 

[Comrade Terry]

If not over 600 or so just stay with the 168 since it is shooting good.

+1, Josh.

 

[Bindi2]

Go online and get the ADI load data for 2208 which is Varget. You are using light loads.

 

[Blackthorn]

I found that my sweet spot 175 SMK load is .018 off the lands ahead of 44.5gr of Varget. This load gave me .382" five shot group at 100yds. I have found that 44.1 and 44.2 give good results also. When I was looking for a 175 load I used Hodgdon's website. I started at 44gr and worked up .1gr ending at 44.9gr (45 is max on the site). Started seeing ejector marks at 44.6 so I stopped there and pulled the remaining test loads.
Going to do chrono work this weekend and finish dialing in my mid-range load..

 

[Wingnut00]

Well, just when I thought I was headed down the right road. Here's the problem - I have been working up 100 yard loads for .308 and settled on Sierra 168gr MK, 43gr Varget, CCI 200 with a .005" jump. These rounds have produced groups of .207" & .250". I wanted to begin same on 300+ yard work up and started with the following - Sierra 175gr., 43gr Varget and a .005" jump. Keeping the jump the constant I began bumping up powder at .3 per 5 shot group. My first 5 shot group at 300yds was crazy wild - maybe 5-6" and the second group was about same. Nothing was even close to a group - holes scattered all over paper. At this point I don't know what to correct next! Should I keep powder at 43gr and start varying the jump .010" - .020"? Very strange - never had such a variance before. The loads were as good as I can make them - Powder throw no more than .1gr var / runout was no more than .002". SD was 9fps and ES was 19. Anybody have any ideas about what I should do next? Thanks in advance for your help.

Maybe I missed it but what twist rate is your barrel.

 

[joshb]

You need to stop and think about what you did. You found a "good load", then "just" changed the bullet. Very bad. You assumed it doesn't make a difference? Reread your manual and Freak's post. This is how you blow up a gun.

 

[tunered]

You need to stop and think about what you did. You found a "good load", then "just" changed the bullet. Very bad. You assumed it doesn't make a difference? Reread your manual and Freak's post. This is how you blow up a gun.

Tell me how to blow up a gun with seating length. Ive been missing something.

 

[seymour fish]

Tell me how to blow up a gun with seating length. Ive been missing something.

He changed bullet weight, in case you are sober now

 

[Shynloco]

Rharris,
What its worth, 168's were not designed to perform at 600 yds. I've shot tons of Sierra 168's dating back to the early 80's and have even talked to the bulletsmiths at Sierra. They recommended that I go to 175's for anything over 400 yds if I'm chasing grouping and best accuracy. And what Boyd wrote is absolutely critical when changing bullet weight. DO NOT assume increasing or decreasing powder loads is the answer when changing bullet weight. That assumption leads to frustration as I have plenty of experience (and frustration) trying to short cut load prep and work up. Just my .02 worth.

Alex

 

[tunered]

He changed bullet weight, in case you are sober now

Yep sober now. Got it. Lol

 

[joshb]

Tell me how to blow up a gun with seating length. Ive been missing something.

A few years ago I did something similar to the OP. I just was getting into "accurate shooting" and the required reloading disciplines. I was not fully aware of all the affects of case volume. I learned that lesson first hand. I had worked up a stout (read as over book) load of Varget with the 168 in my Remington 5r, with the bullet just off the lands. Long throat. By my memory, my COAL was 2.96ish. They wouldn't fit in my mag and I got tired of single feeding so I took 50 reloads and "just" pushed the bullets in to 2.8 and went to the range. The first shot locked up the gun, but it held together. I got it open back at my shop with a rubber mallet and a short piece of 2X4. I stuck my nose back in my books and read every post I could find on case volume as it relates to pressure.

 

[Archer]

op,,,shoot a few of the proven loads again and see if they still work well,,,maby your scope went bad or bedding ,,,check action screws,,,etc,,,,Roger

You might also consider your trigger...sometimes what looks good at 100 can be exaggerated as you move to longer ranges...