6 Competition Match help

[PTflyfish]

Hello. As the thread title says I am seeking help with my 6CM rifle. Earlier this summer I took delivery of a 6CM. The rifle is built on a Borden action with a 28 inch Krieger 8 twist barrel, pillar bedded, barrel free floated. Chamber is cut with reamer designed for Winchester brass and I am shooting Winchester brass. The rifle is set up as per the specs listed by Joesr for the 6CM. I am using the prescribed fireforming load of 47gn H1000 with 107 bullets jammed .020 into lands. Final loads are 49gn to 49.3gn H1000 powder with wither 105 Berger Hybrids or 105 Hornady Amax.
From the searching I have done on this forum results from most people with this caliber seem to be consistently under 1/2 MOA with some getting consistent 1/4 MOA at 100 yards. I am not having these results. My rifle is not shooting consistent groups. FF loads have produced an occasional 1/4MOA group, but normally around 1 MOA to 1.5 MOA with "fliers". Full charge loads are inconsistent as well with an occasional 1/2 MOA group, but more consistent 1 MOA with "fliers". My rifle now has 271 rounds down the barrel. I have done testing at various seating depths with full charge loads ranging from .005 off to .050 off. This testing yielded similar, inconsistent results, nothing stood out as "the load". I have followed the prescribed cleaning and loading methods as laid out by JoeSR.

This is not my first custom build. I have other rifles that are consistent 1/2 MOA rifles and I feel confident in my bench technique to rule out my shooting as a variable. I say that humbly and do not claim to be a bench rest shooter, rather that my shooting technique is consistent enough to produce repeatable results.

I am seeking help/advice from those who have this cartridge or those who have any ideas for me to try. I am hoping that with some tuning/tweaking my rifle will start producing the results that so many have posted about with 6CM's on this forum.

Thank you in advance for any help offered. I am open to posts on this thread or PM's.
Kirk

 

[davidd]

Are you turning your necks?
If not turn to 13.5 thousands and anneal then use a .267 bushing in a FL die. Use an old bore brush to polish the inside of the neck.
Seat the 105 A-Max to 2.80.

 

[PTflyfish]

Thank you for your reply. I currently do turn my necks to 13.5 thousands and I am using a .269 bushing and annealing my brass. I am seating the Amax to 2.318 (case head to ogive) so I am not quite sure how that matches up to 2.80 as I do not have any loaded rounds as I write this. I will give your suggestions a try.

I also am getting a carbon ring around the firing pin after 20 shots. This is with cases that have been fireformed and have only 1 full charge load on them. From my understanding the carbon ring is from leaking primer pockets and/or high pressure. This is concerning to me to be developing loose primer pockets after only 2 firings. Does this seem normal for the 6CM or is this a sign of something wrong? As I said earlier I had the gun set up according to the recommendations for the 6CM by Joesr and am loading for it as prescribed. Thank you for the help.

 

[Capt. Oblivious]

Not a CM but with my SLR I had a couple problems with the brass in the beginning, also Win brass in a 0.272 chamber, what it seemed like was that my neck turner wasn't cutting "into" the shoulder and a small "ridge" was developing or being left behind just above the shoulder after sizing 243 brass to SLR. Had enough one night and turned the necks walls from 13 down to 11thou deep into the shoulder. Problem gone and rifle shoots 87gr VLDs at a blistering speed into one hole and makes very small little groups with 105Bergers as well. I couldn't really pin the 105Amax down even though i really wanted to use them for LR hunting and gave up this past weekend, one day it would shoot neatly and behave and the next time out i would get a crazy flier every now and then to a point where I was starting to even doubt my scope and bedding

 

[Milo 2.0]

Thank you for your reply. I currently do turn my necks to 13.5 thousands and I am using a .269 bushing and annealing my brass. I am seating the Amax to 2.318 (case head to ogive) so I am not quite sure how that matches up to 2.80 as I do not have any loaded rounds as I write this. I will give your suggestions a try.

I also am getting a carbon ring around the firing pin after 20 shots. This is with cases that have been fireformed and have only 1 full charge load on them. From my understanding the carbon ring is from leaking primer pockets and/or high pressure. This is concerning to me to be developing loose primer pockets after only 2 firings. Does this seem normal for the 6CM or is this a sign of something wrong? As I said earlier I had the gun set up according to the recommendations for the 6CM by Joesr and am loading for it as prescribed. Thank you for the help.

Have you really done any proper load development for this rifle? Sounds like you're just trying to run off joesr's recommendations when every rifle is different.

 

[HTSmith]

I also am getting a carbon ring around the firing pin after 20 shots. This is with cases that have been fireformed and have only 1 full charge load on them. From my understanding the carbon ring is from leaking primer pockets and/or high pressure.

No experience with a Competition Match, but that is a problem. Time to recalibrate. A visit to your 'smith is probably in order.

 

[davidd]

How are you fire forming?
Are you jamming them into the lands or do you use a false shoulder?
I also was experiencing loose primer pockets until I went to the false shoulder method of fire forming.
Switching to reloader 26 also helped.
RL-26=MAGIC

 

[PTflyfish]

Thanks to everyone for their suggestions. Davidd PM sent.

 

[Wingnut00]

Hello. As the thread title says I am seeking help with my 6CM rifle. Earlier this summer I took delivery of a 6CM. The rifle is built on a Borden action with a 28 inch Krieger 8 twist barrel, pillar bedded, barrel free floated. Chamber is cut with reamer designed for Winchester brass and I am shooting Winchester brass. The rifle is set up as per the specs listed by Joesr for the 6CM. I am using the prescribed fireforming load of 47gn H1000 with 107 bullets jammed .020 into lands. Final loads are 49gn to 49.3gn H1000 powder with wither 105 Berger Hybrids or 105 Hornady Amax.
From the searching I have done on this forum results from most people with this caliber seem to be consistently under 1/2 MOA with some getting consistent 1/4 MOA at 100 yards. I am not having these results. My rifle is not shooting consistent groups. FF loads have produced an occasional 1/4MOA group, but normally around 1 MOA to 1.5 MOA with "fliers". Full charge loads are inconsistent as well with an occasional 1/2 MOA group, but more consistent 1 MOA with "fliers". My rifle now has 271 rounds down the barrel. I have done testing at various seating depths with full charge loads ranging from .005 off to .050 off. This testing yielded similar, inconsistent results, nothing stood out as "the load". I have followed the prescribed cleaning and loading methods as laid out by JoeSR.

This is not my first custom build. I have other rifles that are consistent 1/2 MOA rifles and I feel confident in my bench technique to rule out my shooting as a variable. I say that humbly and do not claim to be a bench rest shooter, rather that my shooting technique is consistent enough to produce repeatable results.

I am seeking help/advice from those who have this cartridge or those who have any ideas for me to try. I am hoping that with some tuning/tweaking my rifle will start producing the results that so many have posted about with 6CM's on this forum.

Thank you in advance for any help offered. I am open to posts on this thread or PM's.
Kirk

Have you tried retumbo. It's another good one. Mine seems to like h1k and retumbo both and I want to try rl26 also just ain't had time. With Winchester brass and retumbo start out around 48.5gr and work up from there. Also like stated a false shoulder is a must when fireforming.

 

[boltfluter]

Time to try a different powder, if only for a test. Sometimes, for whatever reason, a rifle will just not perform with a powder that everyone else is using. Been down this road myself before. Can be very frustrating to say the least. Do the test and let us know how it goes. Good luck.

Regards, Paul

www.boltfluting.com

 

[Dgd6mm]

I have ff in 3 barrels successfully using H1000. Bullets ranged from 105 H. Amax, 107 SMK, 115 DTAC. On the first Winchester brass I ff I used 47.0 grains of powder with 107's. Next I used any one of the 3 mentioned and 48 grains of H1000. ALL WITH A GOOD JAM IN THE LANDS. All accurate, accurate enough to finish 3rd at Manatee on their steel plate match, 1000 yards 8" gong. I inside neck ream my brass, but not until after the second firing. My fourth barrel that I have not screwed on yet will be shot with reamed brass. I have witnessed with my own eyes very good shooting 6CM's shoot without neck turning or reaming. My finding is of course the prepped necks are more accurate then the nonprepped. But for any shooting steel or paper I would do the necks. It sounds like you are doing all the right things, I would borescope that barrel..... If you would like to talk on the phone send me a p m and I will give you my #. I have a barrel here with over 5100 rounds down it. It has lost mega speed, but will still shoot 1/2" at 100 yards no problem. I, like Joe never have chased the lands,the jump is long. The last ten shot group out this barrel at 215 yards measured 1.049"... while fire forming.... I have targets to prove it.... I know this cartridge pretty well and usually don't go on about it this much anymore because of scepticism. But the proof has always been down range....

Don Dunlap

 

[PTflyfish]

I did some testing today with different fireforming loads and have concluded that I have a bad batch of Winchester brass. I am getting leakage around the primer pockets with new brass during fireforming. I purchased a new bag of Winchester brass from a different lot and will start fresh with different brass. Thanks to everyone for all the help. I will update with results as I get them.

 

[Milo 2.0]

I did some testing today with different fireforming loads and have concluded that I have a bad batch of Winchester brass. I am getting leakage around the primer pockets with new brass during fireforming. I purchased a new bag of Winchester brass from a different lot and will start fresh with different brass. Thanks to everyone for all the help. I will update with results as I get them.

You get leakage around primer pockets from hot loads. You really need to step back and do a proper load workup and not follow what someone else shoots.

 

[Dgd6mm]

His load is not over pressured... No way, no how.... If it's a pressure problem it's being caused from something else.

 

[Milo 2.0]

His load is not over pressured... No way, no how.... If it's a pressure problem it's being caused from something else.

You're saying gas escaping primer pockets normal or what, something's causing this. My comp match pressures up at 48gr of 7977 with a 105 hybrid, the sierra he's using has got to produce more pressure.
Every rifle is different.