Need some input from more knowledgeable people on this.
I'm starting to beat my head against a wall on this. I bought a Savage 12 Benchrest used that had a low round count. I started w/ a .308 load similar to the load I used in a 10BA. The 10BA shot sub 1/2 MOA at 100 when testing loads and held .50 MOA out to 500 on a regular basis. I shot it many times at 1,000 at it did pretty well with this load.
I started out with same load for the 12 BR model and it did not respond. The rifle clearly liked a different load. So I played with powder to find a node and it also clearly liked a jump and I had to load them shorter.
So after I found a powder weight and velocity that worked well, I played with seating depth. The thing shoots killer at 100 yards < .50 MOA hole in hole type groups. However, when you take it to 500 or 1,000, compared to my other gun it shoots like crap. I've played with everything I can think about up and down and it seems like the gun just will not shoot. To remove the re-loading variable, loads done in the same equipment and process shoot great in my other rifle.
So my question is, what am I missing in this equation? It seems to like a lot of jump (around .035" has been best so far). I'm starting to think the barrel sucks and may need to re-barrel.
Here are the specifications:
Lapua brass, fired formed
CCI 200 or Fed 210 primers
43.5g Varget seems to be most accurate so far in Lapua, 43.7 in Win
175g SMK
Neck concentricity around .001"
Velocity is around 2750
I've chrono'd and had pretty good ES numbers. I'm at a loss with this gun!
Did you work the load at 100 yards? It is not uncommon for the best load at 100 not work well at longer distaces. Before you do anything drastic, do your load work at 300 yards. Everything should have settled down at that point.
If that doesn't work then I would look at subtle things to see if you have anything causing bullet deformity.
More shooting, less typing.
Good grouping at close range. Bad grouping at long range.
What scope are you using ?
What magnification are you shooting at?
How have you checked the parallax at either ranges ?
Is the parallax adjustable ?
Maybe you need more magnification ?
I have a model 10 wearing a Shilen 1:10 26" varmint barrel and shooting a very similar load to yours and mine shoots 1 hole groups at 100 yards and is less than 1MOA (including wind variation) at 320. Last time out I had 15-15mph direct cross wind.
what twist?
Life is tuff.....its even tuffer when your stupid
{John Wayne}
+1, 300 yards will tell you much more about a load than at 100 yards. Are your Standard Deviation (SD) and Extreme Spread (ES) number very low teens or single digit? How many loads on the Lapua brass, it may be time for neck annealing. Try going to a match primer for the long range loads...Originally Posted by Jamie
To respond to above:
Did loads at 100 and 500. 100 is good, 500 not what I would expect.
1/12 twist
Nightforce NXS 12-42. Yes adj parallax.
12X at 100, around 20X at 500.
Isn't the 1:12 twist a little slow for the 175 SMK?
I have to agree with what others have said...try your load development at 300 yards and switch to a match/bench rest primer (I have had great luck with Fed 210M's in my 308's)....the other problem is likely the twist rate of your barrel... 1:12 may well be a little to slow for 175 class bullets...
Why is 300 yards better for load development than 500?
Based on all the feedback here and from others, probably looks like the 175 is the problem w/ the 1/12 twist.
No one is saying 300 is better than 500. What they are saying is 300 is better than 100. The 175 should do fine in the 12 twist. If you are not seeing any keyholes in the target you just need to find the right load. What powders have you tried? I see you are using Varget. I tried and never could get a load to work with varget and 175's. Ended up going to BLC-2. Not saying that will work for you but don't be hung up on one powder. Every barrel is a creature unto itself.
"And you shall know the truth, and the truth shall make you free.” John 8:32 (New King James Version)
I guess some missed the part where I stated I was also testing loads at 500 above.
"when testing loads and held .50 MOA out to 500 on a regular basis."
I've been testing at both 100 and 500. 500 is where I see the problem on one gun and not another. One holds around .50 MOA at 500 on a good day, the other typically around 1.
Starting to look like it does not like 175 SMK or the barrel is south.
We are not saying to test the load at 500, we are saying work the loads up using longer distances to start with. Just because one load in one rifle will work at both distances doesn't mean they all will. Bullets move around more than most people think when fired and takes time to settle and go to sleep.
Last edited by Jamie; 05-12-2014 at 07:47 AM.
More shooting, less typing.
I'm going to try the 155 Scenars in this rifle. I will test them at 500 and then 1,000 against the 175 SMK's and see how they compare.
I guess the easiest way to explain it is to forget about groups at 100 yards. Go through your load process but do all the shooting at longer ranges. If a load works at 500 then it will most likely work at longer ones. Basically start over just use a distance longer than 100.
More shooting, less typing.
Regarding load development (not nec. in this order)...
#1 - The yardage needs to be [A] short enough that conditions are as close to nil effect on the trajectory as possible (choose a day when it is very calm), and [B] long enough such that the bullet has fully stabilized. For most, this would be between 200 and 300 yards. But IF (big if here) conditions allowed, further is better.
#2 - Ensure the bullet you are developing with will use a sufficient charge to remain stable all the way to the target (current and at the longest range you expect to shoot that load) . That ALSO includes not choosing a bullet which is marginal to the barrel twist rate (optimal is fine... even overly so - but under-stabilization from an improper twist-rate for a particular bullet length will never yield great - or consistent - results).
#3 - Consider developing a load using a set of ladder tests as a starting point. You'll shoot less, but gain more insight into where the nodes are. Then you can get more detailed with-in +- a few tenths
#4 - Chronographing is an absolute MUST. Without that data, you'll have no idea what to attribute inconsistencies to. ES and SD numbers combined with your targets are going to save you loads of time...
just my 2 cents...
.22LR * 6.5x47 Lapua * .223 Rem * .308 Win * 260 Rem * Large Cojones!
[I]"I can prove anything by statistics except the truth."[/I]
Thanks for the feedback. I have done pretty much everything you recommended above with the exception of 200-300 yard testing. This is an F/TR gun I planned on using for 1,000 yard matches. We have shot it both in testing at 1,000 matches. Based on the results of the last 1,000 yard match, I knew something was wrong. So the last load testing I did at 500, mostly to just check vertical. I have done various ladder tests and chrono and used a bullet for the application (or I thought).
I'm coming to two conclusions:
This gun being a 1/12 twist gun (checked this AM and got 1 in 12.25") does not like/want to shoot a 175 SMK regardless of the velocity and seating depth.
The barrel is bad, or both.
I'm having the barrel looked at Wed and will start over with some 155 Scenars before I give up and re-barrel.
Pretty much every twist rate chart I have seen shows 1:12 in 308 only good up to 170g pills....my 10 cents worth is that's most likely your problem.
Yes, live and learn. I took someones word that it shot 175's well.
Ordered the Scenars today. Will report back how they shoot.
For what it's worth, I have had really good luck in one of my 308's that has a 1:12 with 168g Nosler Custom Competitions....
I have not seen any data on these at 1,000? I'm trying to stick (or at least try) with bullets that have some track record of 1,000 yard F/TR class.
Now that we know that your loads are ok,lets talk about your front rest and rear bag.Could you tell us what you are shooting off ? Does the gun return to zero when fired or do you have to continually readjust to make the next shot.If the gun jumps then we can explore ways to cure it.
Willing to give back for what the sport has done for me!
Here a picture (or video) is worth 1,000 words. My 15 year old son is doing the shooting in the matches and testing, I do the loading and all the prep. He keeps it on target pretty well after the shot.
I'm more and more convinced it's the bullet I was using.
Ive seen 1-12tw. barrels do outstanding with lighter projectiles 150/155.
My 10 FCP-HS-5R 24" 11.25twist gives me .25moa @ 100 (with 150smk) and flys nice and tight out to 1k easily even in 20mph winds. Ive shot against shooters who were shooting 168a-max-168-175 SMK and when all was said and done, I only had to adj. 1moa more for windage compaired to there weight of pill at 1K distance.
I truely believe that you might be spot on on your evaluation.
Nothen better than to watch your off spring enjoying our 2nd amend.
he looks nice and steady
I surely miss having my son around on shooting sundays.
Life is tuff.....its even tuffer when your stupid
{John Wayne}
I have a 7mm08 with a 1 to 11 inch twist rate and it doesn't like anything over 140 grain in Nosler at all.
GLC
Most all twist rate charts show you'd need a 1:10 twist in a 7mm-08 in order to properly stabilize a 140g class bullet....
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