6mm Creedmoor accuracy

[spudgun]

I have a savage with a Wilson barrel in 6mm CM. At first it shot great getting 3" groups at 600 yds. My load data is:

40.6 G, H4350, 105g Hornady match, Starline SP brass, CCI #41 primers, 2900-2950 FPS.

I have now a issue with my groups, getting 6 to 10" groups at 600 yds with this load.

Now I did change 1 varaible, With the shortage of CCI #41, I went to using Winchester WSR.

Now my FPS remained at 2900 - 2950 and all other components have stayed the same.

I have about 1500 rounds down the barrel and have not seen any issues with the rifling or fouling.

Will a primer change cause this type of change in my groups??

 

[acloco]

Maybe.

Rule in reloading - change ANY component, you need to start over.

Unfortunately, there is not fast track to accuracy/functionality/etc/etc.

 

[spudgun]

Maybe.

Rule in reloading - change ANY component, you need to start over.

Unfortunately, there is not fast track to accuracy/functionality/etc/etc.

Yeah, I know this but just didn't want to go through the many ladder testing again. Weather getting cold and don't know if I have time develop a load before the snow sets in.

It took me 3 months to find the load that the gun liked.

Don't know if the CCI primers were making the differance.

Hoping they would not.

I was sure what the differance between CCI and Winchester primers were. My thought was if the FPS stays the same using the Win primers everything should stay the same.

I could be wrong (and maybe I am).

 

[RGRobinett]

For the Creedmoor capacity, & 6mm bore, 1500 rounds may be the end of the line. RG

 

[spudgun]

For the Creedmoor capacity, & 6mm bore, 1500 rounds may be the end of the line. RG

Yeah, thought about that too.

 

[Texas10]

You have a Savage....that's prone to loosening of the action screws. Have you torqued them lately? Have you torque tuned the rear action screw?

I was at the public range recently when a couple of guys with 6.5CM were complaining about how their Savages, both 12FV's had lost their accuracy over the years shooting factory ammo. I took a look at them and both had very loose action screws. I torqued them up and then performed a torque tune and had them both shooting better than ever. Never seen two guys so happy after just a couple minutes work!

 

[spudgun]

You have a Savage....that's prone to loosening of the action screws. Have you torqued them lately? Have you torque tuned the rear action screw?

I was at the public range recently when a couple of guys with 6.5CM were complaining about how their Savages, both 12FV's had lost their accuracy over the years shooting factory ammo. I took a look at them and both had very loose action screws. I torqued them up and then performed a torque tune and had them both shooting better than ever. Never seen two guys so happy after just a couple minutes work!

yes, I also had action screws loosen up (also the scope base screws too). The stocks have been bedded and pillered.

That was one of the first things I checked when the groups started to open up.

Thanks for reminder though...

 

[Matt_3479]

Have you bore scoped it? Carbon ring? Have you check your seating depths lately for erosion. After 300-400 rounds I had to seat out my 6 creed slightly to tighten up my groips

 

[Ranger188]

It could be a combination of all of those things.
**1500 rounds
lands eroding
changing primers
brass wearing out
You might not have been in the center of that node
Add all that up and yes your groups will start to change.

 

[acloco]

Yeah, I know this but just didn't want to go through the many ladder testing again. Weather getting cold and don't know if I have time develop a load before the snow sets in.

It took me 3 months to find the load that the gun liked.

Don't know if the CCI primers were making the differance.

Hoping they would not.

I was sure what the differance between CCI and Winchester primers were. My thought was if the FPS stays the same using the Win primers everything should stay the same.

I could be wrong (and maybe I am).

Running a load ladder is not that difficult or time consuming (should NOT be a chore).

Search on this site or google "modified Audette Load Ladder".

Ten shots initial load ladder. Two to four more individual strings from data on your first ten. Usually, barrels provide two distinct nodes of accuracy. Concentrate on those nodes and work from there.

 

[rickt300]

Well 1500 rounds and starting a new load work up might finish the old girl off. Might be time for a set back and rechamber.

 

[spudgun]

Well 1500 rounds and starting a new load work up might finish the old girl off. Might be time for a set back and rechamber.

I had this same discussion over breakfeast with another long distance shooter that I shoot 1000 yds with. He said the same thing.

 

[rickt300]

It is sad to me just how short barrel life really is if you shoot a lot. I have a backyard range that goes to 200 yards and it is nothing for me to pop 40-50 rounds at a sitting. That is only 30 trips from my loading bench to my shooting bench.

 

[vegas]

It is sad to me just how short barrel life really is if you shoot a lot. I have a backyard range that goes to 200 yards and it is nothing for me to pop 40-50 rounds at a sitting. That is only 30 trips from my loading bench to my shooting bench.

Sounds like a terrible problem to have

 

[winters7746]

I have a savage with a Wilson barrel in 6mm CM. At first it shot great getting 3" groups at 600 yds. My load data is:

40.6 G, H4350, 105g Hornady match, Starline SP brass, CCI #41 primers, 2900-2950 FPS.

I have now a issue with my groups, getting 6 to 10" groups at 600 yds with this load.

Now I did change 1 varaible, With the shortage of CCI #41, I went to using Winchester WSR.

Now my FPS remained at 2900 - 2950 and all other components have stayed the same.

I have about 1500 rounds down the barrel and have not seen any issues with the rifling or fouling.

Will a primer change cause this type of change in my groups??that has happened to me before , throat erosion causes you to have adjust seating depth about every 100 rounds or so. then groups will tighten back up

 

[winters7746]

my bartlein barrel 284 Winchester requires me to adjust seating depth every 100 rounds. just .005 throat erosion causes my groups at 600 to go from under 2 inch to jump up to 6 inch groups. I adjust out .005 and tightens back up. do a seating depth test to find its new best depth will fix problem

 

[spudgun]

my bartlein barrel 284 Winchester requires me to adjust seating depth every 100 rounds. just .005 throat erosion causes my groups at 600 to go from under 2 inch to jump up to 6 inch groups. I adjust out .005 and tightens back up. do a seating depth test to find its new best depth will fix problem

My thoughts were like yours. It could be I need to seat the bullet out.

I just came from the 600 yd range and it was too cold to do ladder testing now.

I am going to wait for a better day to try different settings (damm winter).