6XC ground truth as of Jan 2020?

[6xcshooter]

All the reamer talk about a 6xc is not applicable to me. I make a dummy round seated to the depth I want send it to my gunsmith (Greg Tannel ) and have the barrel chambered to the dummy load. Got Four of them they all shoot lights out. With berger 105s and 115 dtacs using h4831sc i can achieve over 3100 fps with both bullets. My go to powder is h4350 with 39 to 39.5 grains. Al my 6xcs shoot it excellently.

 

[Hoot]

If new cases fit with clearance I don’t understand why headspace could be the issue. Once fired the case will conform to the chamber minus some spring-back.
Looks like it shoots.

Thanks guys. Both new and .002 setback FL resized, fired cases drop in and fall out without any resistance. I was trying to get some of your ideas as to why I experience hard bolt lift, top of lift click and slight swipes with any load approaching modest speeds, with multiple bullets. (not hot loads) So, I was trying to read the "tea leaves" from my spent brass. If I were not experiencing those three symptoms, you would not be hearing from me as I'm more than pleased with the accuracy results.

I'm not a competition shooter. I just love experimenting and that includes bullets, brass and powders that are not prime candidates for competition. If I were just interested in the best competitive odds, choices and challenges would be simple. I'm a troubleshooter by trade and it shows in what interests me as a hobby. I am not a frustration fan however and like to occasionally triumph over the challenges I choose. Truth be told. If this rifle and caliber choice worked flawlessly right out of the chute, with no need for thought or room or improvement, it would have already joined the other rifles I have like that, sitting in the back of my safe. I do enjoy and am a proponent for the free and open sharing of what helps, to anyone who asks. They are not my competition and I'm not theirs.

For another member who asked earlier. I weighed a random dozen of the new SRP brass I recently got from SSS and a dozen of the $30/100 "value ones" I got back in 2018.

Of the 12 I recently got, Ten weighed within .5 gr of one another ranging from 165.3-165.8. Two were slightly heavier at 166.0 and 166.3. Untrimmed lengths ranged from 1.901-1.902 and .375 datum ranged from 1.513-1.514.
Of the 12 "value ones" from 2018, Eight weighed within .5 gr of one another 165.2-165.7. the Four outliers were 163.7, 164.4, 164,6 and 165.0. Untrimmed lengths ranged from 1,892-1,894 and .375 datums ranged from 1.511-1.512. Hope that helps.

 

[spclark]

Thanks Hoot, that's useful info.

Here're some numbers I gathered years ago, two random of each type of brass I'd shot with:

R/P 22-250 > 6XC 151.4 gn
Tubb Gen III 6XC 154.8 gn
Norma 6XC 157.5 gn
WIN 22-250 > 6XC 159.1 gn
Norma 22-250 > 6XC 160.4 gn
Lapua 308 "Palma" > 6XC 165.9 gn
Tubb Gen I 6XC 171.9 gn

(Of these the longest-lasting and consistently best performing was the Lapua Palma 6XC, but a major PITA to form up!)

- and just recently (five random cases each) :

Alpha SRP 6XC 157.04 - 157.72 gn (lot #01A390415E7)
Peterson SRP 6XC 161.32 - 161.68 gn (lot #W1TL0136 QC0222119)
Peterson SRP 6XC 165.54 - 166.02 gn (no lot#, sourced from Tubb)

So I'm patiently waiting for more amenable weather to load up these three newest arrivals, see how they behave 'under fire' at 600 yards.

 

[Stumpy1]

Thanks guys. Both new and .002 setback FL resized, fired cases drop in and fall out without any resistance. I was trying to get some of your ideas as to why I experience hard bolt lift, top of lift click and slight swipes with any load approaching modest speeds, with multiple bullets. (not hot loads) So, I was trying to read the "tea leaves" from my spent brass. If I were not experiencing those three symptoms, you would not be hearing from me as I'm more than pleased with the accuracy results.

Hoot, you mentioned that you got your barrel from Northland, a Criterion Remage. You also showed the reamer print with a 0.275 neck diameter. I have the same thing with a Savage Criterion barrel from Northland (my wife's rifle).

In our hands using Peterson brass, the neck 'clearance' can be dangerously tight. I think the 0.275 neck diameter is too small for Peterson brass, and will be spec'ing a reamer with a larger neck diameter going forward.

What is your loaded round neck diameter? (with a micrometer, not a caliper)
Too tight will definitely produce high pressure at less than normal 'max' loads.
The solution might be to turn necks slightly, or use thinner neck wall brass.
You can also have a smith run a neck reamer into your chamber to open it up.

Also, check for neck peening if you are using stainless tumbling for cleaning -I have seen this with other folks ammo.
The solution for this is to chamfer inside and outside every time.

If this 'stuff' has already been considered, well, I got nothin'

Hope this helps,

Frank

 

[tclaunch]

Hoot, you mentioned that you got your barrel from Northland, a Criterion Remage. You also showed the reamer print with a 0.275 neck diameter. I have the same thing with a Savage Criterion barrel from Northland (my wife's rifle).

In our hands using Peterson brass, the neck 'clearance' can be dangerously tight. I think the 0.275 neck diameter is too small for Peterson brass, and will be spec'ing a reamer with a larger neck diameter going forward.

What is your loaded round neck diameter? (with a micrometer, not a caliper)
Too tight will definitely produce high pressure at less than normal 'max' loads.
The solution might be to turn necks slightly, or use thinner neck wall brass.
You can also have a smith run a neck reamer into your chamber to open it up.

Also, check for neck peening if you are using stainless tumbling for cleaning -I have seen this with other folks ammo.
The solution for this is to chamfer inside and outside every time.

If this 'stuff' has already been considered, well, I got nothin'

Hope this helps,

Frank

My reamer is based off Robert Whitley`s XC II and the neck diameter is .2748" at the case mouth, and I will definitely be turning the necks to .014"

This is quite possible Hoots nemesis.

 

[Dgd6mm]

I typically shoot my 6XC's over 3150fps with 115 DTACs and reload the brass with snug primer pockets. ALL of the 6XC Peterson brass sold by SSS was never any part of the 1st batch that Peterson ran.
I told them to scrap the 1st batch.. and they sold it to grafs. What a f%$*mess they created IMO..

If you know anything about 6XC resize dies and peruse what is offered there is NO comparison between SSS 6XC S7 tool steel resize die with integral neck shoulder bushings. Every other 6XC resize die(s) are like comparing a "Volkswagon to a Ferrari" (Redding employee comparison years ago at the SHot SHow)
But what do I know..

 

[Dgd6mm]

1. Over the years that SSS handled Norma their head hardness was comparable to the Peterson.
2. Compare prices - SSS prices are 30-40 cents less. Large or small primer.

 

[Dgd6mm]

My recommendation would be sole sourcing - if possible- for any product you have an interest in. I designed the 6XC (6x48) so it would be logical (at least to me) to buy all my components/reamers/dies from a single source (not to mention better component pricing).
Even has a CIP designation - the other offshoots do not.

 

[Dgd6mm]

There are times when we, as shooters, are our own worst enemies. Sole source supply often irritates some folks because they think it's a monopoly and the owner is making rapacious profits. So we shop the idea around looking for alternatives ways to save money and disconnect from the sole source supply.

But, and this is a big but, this instance has one of the best shooters in the country who has been refining this cartridge and bullet design on his own dime while offering to supply us with the products he finds to be the best for the money and for performance.

I have one of the original chambers for the XC which was done with a reamer from a second source. I bought Norma brass and I was able to make it shoot as advertised. But I spoke with David at one of the shows, probably S.H.O.T., discussing the II version of the XC cartridge. I ordered the reamer, dies, brass and bullets for a rifle I finally got built this last summer. It shoots as advertised with the load work up and loading suggestions from David. This is a very mild yet accurate cartridge for 600 to 1,000 yard competition. It's just plain enjoyable to shoot.

 

[Dgd6mm]

When designing the 6XC one of the main design parameters was being able to seat a 115 gr 6mm bullet into the case and still be able to feed it out of the magazine box while allowing the OAL a reasonable length to grow with throat erosion.
Keep in mind that the 6XC is approximately .050" (2 millimeters) shorter than a creedmore case. This is a "BIG" deal of the 6XC design.
With a .130" straight section and a 1 1/2 degree lead the 6XC with a 115 DTAC allows over a .020" clearance distance between the full diameter at the base of the bullet and the neck shoulder junction of the 6XC case ( it will never encounter the DONUT). The sets a newly chambered 6XC's OAL starting seat length to 2.780".
In most short action magazine boxes the internal useable length is 2.850".. This allows the 6XC user to be able to seat their bullet .070" longer as their throat grows over the life of their barrel and still reliably feed out of their magazine box.

A creedmoor based case as starts out .050" longer than a 6XC case. So from the get go the magazine is beginning to approaching a OAL seating length issue. The creedmoor can grow .025" before encountering the magazine box internal length issue.
Also the extra .050" of the creedmoor case length doesn't yield any appreciable velocity increases when compared to the 6XC.

I tried the 6XC with a 6.5 bullet (7mm also) when I was doing 6XC developmental work. My parameter with the 6.5XC was to allow a 142 sierra to be seated as above and still have room to grow .070" as well as full bases diameter clearance of the neck shoulder junction. The 6.5 creedmoor case exhibits the .050" (2 millimeters) so it will be crowding the OAL box mag length.

And you ask - Why didn't I pick a 6.5XC from my testing years ago.. in every respect (other than barrel life) it cant hold a candle to the 6XC.

 

[Dgd6mm]

H4350 or IMR 4451 treated with TUBBDUST. Slightly above or below 41 grains
Shooting out of a TUBBGUN with a 30-31" Schneider 5P 7twist barrel.. I have had a couple of barrels that would yield 3225 fps but that load is a max load.
Using S&B large rifle primer which is a mild primer which typically allows more velocity with less pressure. Russian primers were well back from these velocities with pressure signs.
Coated 115 DTAC can touch or jump doesn't matter. Which ever shoots the best.

 

[Dgd6mm]

Current 6XC reamer prints can be found on the TUBB original 6xc and 33xc/37xc page

Major specs
base .470
Neck .278
Leade .160
Throat Angle 1 1/2

user can get by with a .130 leade and still stay in front of the donut

 

[Dgd6mm]

^^^^^^^ if I ever decided to pursue the 6xc I'd do what David suggests. I did it and do it with the Competition Match and Joe Hendricks has not steered me wrong.

 

[BOB LEE SWAGGER]

For anyone who is thinking about a 6XC, don't be confused this is a GREAT and EASY cartridge to shoot well. I started with a 6XCII using (of course) the reamer recommended and available Redding 6XCII sizing die. Norma and Alpha brass both yielded excellent results (Alpha, RL16/39.1, 108BT & 205M) the best for me.

I have just gone the "sole sourcing" route because of my belief in DTUBB. Not to be petty but I don't like the name of 6XCII - II usually a designation of improved. I recently purchased reamer, seater, Petersen SRP brass & DTACs from SSS. I have a BRUX 32" 1:7 twist barrel as well. Oddly enough I have yet to be resolved (by me) issues from the "sole sourcing". The PTRSRP loaded round diameter is .27395-.274. The SSS sizing die includes a .266 & .268 bushing. The .268 bushing sized my necks a bit under .268. I only sized and loaded 5 because of the force needed to seat. I then sized and used a .241 mandrel to expand. I used the Redding/SSS seater to seat 109 Bergers, 108 Bergers and Sierra 110s all good. But the DTACs... The deep ring around the DTAC seated in the original 5 sized (not expanded) pieces of brass was lessened yet still prominent on the nose of the DTAC seated in the sized and expanded brass. I used the non custom Redding 6XC seating die with many a DTAC and never had a problem, so I'm hoping that will be the solution for seating. Conclusion: The brass and sizer die from the same source don't work together and the seating die and the bullets from the same source don't work together.
Easy enough solutions. Expand brass or use Norma. Save the custom seater for bullet other than DTAC. Minor turbulence for a phenomenal cartridge.

 

[Dave Marshall]

For anyone who is thinking about a 6XC, don't be confused this is a GREAT and EASY cartridge to shoot well. I started with a 6XCII using (of course) the reamer recommended and available Redding 6XCII sizing die. Norma and Alpha brass both yielded excellent results (Alpha, RL16/39.1, 108BT & 205M) the best for me.

I have just gone the "sole sourcing" route because of my belief in DTUBB. Not to be petty but I don't like the name of 6XCII - II usually a designation of improved. I recently purchased reamer, seater, Petersen SRP brass & DTACs from SSS. I have a BRUX 32" 1:7 twist barrel as well. Oddly enough I have yet to be resolved (by me) issues from the "sole sourcing". The PTRSRP loaded round diameter is .27395-.274. The SSS sizing die includes a .266 & .268 bushing. The .268 bushing sized my necks a bit under .268. I only sized and loaded 5 because of the force needed to seat. I then sized and used a .241 mandrel to expand. I used the Redding/SSS seater to seat 109 Bergers, 108 Bergers and Sierra 110s all good. But the DTACs... The deep ring around the DTAC seated in the original 5 sized (not expanded) pieces of brass was lessened yet still prominent on the nose of the DTAC seated in the sized and expanded brass. I used the non custom Redding 6XC seating die with many a DTAC and never had a problem, so I'm hoping that will be the solution for seating. Conclusion: The brass and sizer die from the same source don't work together and the seating die and the bullets from the same source don't work together.
Easy enough solutions. Expand brass or use Norma. Save the custom seater for bullet other than DTAC. Minor turbulence for a phenomenal cartridge.

If both seating dies are Redding, you could likely swap the seater stem and solve your bullet ring problem. The contour of the seating stem is what typically causes seating dies to leave a slight ring on bullets.

 

[J.d. Popkes]

For anyone who is thinking about a 6XC, don't be confused this is a GREAT and EASY cartridge to shoot well. I started with a 6XCII using (of course) the reamer recommended and available Redding 6XCII sizing die. Norma and Alpha brass both yielded excellent results (Alpha, RL16/39.1, 108BT & 205M) the best for me.

I have just gone the "sole sourcing" route because of my belief in DTUBB. Not to be petty but I don't like the name of 6XCII - II usually a designation of improved. I recently purchased reamer, seater, Petersen SRP brass & DTACs from SSS. I have a BRUX 32" 1:7 twist barrel as well. Oddly enough I have yet to be resolved (by me) issues from the "sole sourcing". The PTRSRP loaded round diameter is .27395-.274. The SSS sizing die includes a .266 & .268 bushing. The .268 bushing sized my necks a bit under .268. I only sized and loaded 5 because of the force needed to seat. I then sized and used a .241 mandrel to expand. I used the Redding/SSS seater to seat 109 Bergers, 108 Bergers and Sierra 110s all good. But the DTACs... The deep ring around the DTAC seated in the original 5 sized (not expanded) pieces of brass was lessened yet still prominent on the nose of the DTAC seated in the sized and expanded brass. I used the non custom Redding 6XC seating die with many a DTAC and never had a problem, so I'm hoping that will be the solution for seating. Conclusion: The brass and sizer die from the same source don't work together and the seating die and the bullets from the same source don't work together.
Easy enough solutions. Expand brass or use Norma. Save the custom seater for bullet other than DTAC. Minor turbulence for a phenomenal cartridge.

Wouldn’t a larger bushing work?

 

[BOB LEE SWAGGER]

Wouldn’t a larger bushing work?

Yes if available. The SSS sizer die is proprietary with two neck/shoulder bushings included - .266 & .268. I would jump on a .271 version.

 

[J.d. Popkes]

Yes if available. The SSS sizer die is proprietary with two neck/shoulder bushings included - .266 & .268. I would jump on a .271 version.

Oh, ya I forgot about that. I use a 270 bushing in my Whidden, hmm

 

[js2013]

Hoot, you mentioned that you got your barrel from Northland, a Criterion Remage. You also showed the reamer print with a 0.275 neck diameter. I have the same thing with a Savage Criterion barrel from Northland (my wife's rifle).

In our hands using Peterson brass, the neck 'clearance' can be dangerously tight. I think the 0.275 neck diameter is too small for Peterson brass, and will be spec'ing a reamer with a larger neck diameter going forward.

What is your loaded round neck diameter? (with a micrometer, not a caliper)
Too tight will definitely produce high pressure at less than normal 'max' loads.
The solution might be to turn necks slightly, or use thinner neck wall brass.
You can also have a smith run a neck reamer into your chamber to open it up.

Also, check for neck peening if you are using stainless tumbling for cleaning -I have seen this with other folks ammo.
The solution for this is to chamfer inside and outside every time.

If this 'stuff' has already been considered, well, I got nothin'

Hope this helps,

Frank

Good info. My findings match yours. Thanks

 

[spife7980]

Hoot, you mentioned that you got your barrel from Northland, a Criterion Remage. You also showed the reamer print with a 0.275 neck diameter. I have the same thing with a Savage Criterion barrel from Northland (my wife's rifle).

In our hands using Peterson brass, the neck 'clearance' can be dangerously tight. I think the 0.275 neck diameter is too small for Peterson brass, and will be spec'ing a reamer with a larger neck diameter going forward.

What is your loaded round neck diameter? (with a micrometer, not a caliper)
Too tight will definitely produce high pressure at less than normal 'max' loads.
The solution might be to turn necks slightly, or use thinner neck wall brass.
You can also have a smith run a neck reamer into your chamber to open it up.

Also, check for neck peening if you are using stainless tumbling for cleaning -I have seen this with other folks ammo.
The solution for this is to chamfer inside and outside every time.

If this 'stuff' has already been considered, well, I got nothin'

Hope this helps,

Frank

I noticed that potential clearance issue as well with a .275 neck in the criterion 6xc in my remage.

Loaded round neck diameters are .272 for peterson and .269 with norma.
Fired brass out of my criterion 6xc measure .274 and thats for both peterson and norma so that backs up the .275 chamber figure well enough.

So only .003 of clearance with the peterson. I havent found that thick brass to be an issue though other than my forster die, which I had honed .265 for my norma brass, is overworking the peterson before I mandrel it back open. I havent had any pressure signs after 4 firings of my peterson brass yet so Im less concerned with the clearance now.


My only issue is that Im struggling to get the 103eldx and the 90 tgk to shoot as well as the 105 rdf. And since I intended this rifle to be a hunter... thats annoying. And thats with both norma and peterson. I would toss it except as a last grasp I discovered it DOES like the match bullets...