6XC Alpha brass and bolt stickiness.

[DarkStar]

Question about some bolt stickiness. I have some 6XC Alpha brass (SRP). Fired all of them once. 38.5 grains H4350 I had maybe one or two cases out of 22 that had enough stickiness to cause me to have to pop the bolt at the top (Tubb 2000 rifle). With 39.0 grains, about the same thing. Anyway, tested up to 39.9 (and appx 3075 fps) at the house, had sticking on most. Reduced to 39.6, sticking went away.

Anyhoo, went to an XTC match and used the load with 39.6 grains. It was a pretty hot day and almost every round with this load had to get the bolt popped at the top.

I realize that the common sense answer would be to go back to the 39.0 or 38.5 loads. That said, still had a few sticking cases there as well.

So here's the question: Given that this is Alpha brass, would it be worth it to get a 6XC II reamer?

I have never had a problem with Norma brass being sticky. Still want to keep giving the Alpha brass a whirl.

 

[shotdown]

Yes, Alpha recommends a 6XC II reamer. In reality, you need a reamer with a web area at .4705 or larger, and a .275 neck or larger. Anything under that, they recommend sizing the virgin brass and it should prevent bolt lift issues.

I personally am using a reamer with .4705 web and .275 neck. I am running virgin brass as is with no issues.

 

[DarkStar]

Thanks. This virgin brass was sized in a Redding Type S 6XC die prior to firing.

I do have a Tubb 6XC die, but I didn't use it sizing these cases.

 

[Goldenfinger]

Question about some bolt stickiness. I have some 6XC Alpha brass (SRP). Fired all of them once. 38.5 grains H4350 I had maybe one or two cases out of 22 that had enough stickiness to cause me to have to pop the bolt at the top (Tubb 2000 rifle). With 39.0 grains, about the same thing. Anyway, tested up to 39.9 (and appx 3075 fps) at the house, had sticking on most. Reduced to 39.6, sticking went away.

Anyhoo, went to an XTC match and used the load with 39.6 grains. It was a pretty hot day and almost every round with this load had to get the bolt popped at the top.

I realize that the common sense answer would be to go back to the 39.0 or 38.5 loads. That said, still had a few sticking cases there as well.

So here's the question: Given that this is Alpha brass, would it be worth it to get a 6XC II reamer?

I have never had a problem with Norma brass being sticky. Still want to keep giving the Alpha brass a whirl.

Read through this.
http://www.6mmar.com/6XC_II.php

 

[spife7980]

1) What bullet are you using?
I am using 39.4 of H4350 behind a 105 rdf in norma and I get 2995 fps and Im not far from max ejector marks. If you are using a 105 then your velocities of an extra 100 fps tell me that you are pushing it hard which makes me thing that the alpha is probably a thicker material/smaller internal volume which is leading to more pressure.

2) You said "fired them all once" Are these sticky brass occurring during that initial firing of the virgin brass or are these sticky cases on the second firing with the reprocessed brass? If its the first firing then I would say thats because the brass isnt fire formed and has a smaller internal volume than fire formed brass will.

3) Do you have a micrometer (preferable) or caliper (will suffice) to measure some virgin, fired and sized case diameters with? ~.463" would be the gen 1 reamer design for 22-250 brass, ~.469 would be the gen II for 308 brass.

I would say its due to the genI vs genII but if that were the situation I would think that norma would be presenting the same issues. But you say it doesnt which is pointing me away from that as the issue.

 

[DarkStar]

1) What bullet are you using?
I am using 39.4 of H4350 behind a 105 rdf in norma and I get 2995 fps and Im not far from max ejector marks. If you are using a 105 then your velocities of an extra 100 fps tell me that you are pushing it hard which makes me thing that the alpha is probably a thicker material/smaller internal volume which is leading to more pressure.

2) You said "fired them all once" Are these sticky brass occurring during that initial firing of the virgin brass or are these sticky cases on the second firing with the reprocessed brass? If its the first firing then I would say thats because the brass isnt fire formed and has a smaller internal volume than fire formed brass will.

3) Do you have a micrometer (preferable) or caliper (will suffice) to measure some virgin, fired and sized case diameters with? ~.463" would be the gen 1 reamer design for 22-250 brass, ~.469 would be the gen II for 308 brass.

I would say its due to the genI vs genII but if that were the situation I would think that norma would be presenting the same issues. But you say it doesnt which is pointing me away from that as the issue.

1.) Berger 105 Hybrids

2.) Virgin, previously unfired, but run through Redding Type S die, on their initial firing.

3.) That answer will have to come tomorrow. My micrometer and calipers are packed up due to Hurricane Florence. IIRC, the Norma case heads (fired 12 times) were closer to .469, but my gunsmith who cut the chamber said it was a gen I 6XC reamer.

 

[DTubb]

Thanks. This virgin brass was sized in a Redding Type S 6XC die prior to firing.

I do have a Tubb 6XC die, but I didn't use it sizing these cases.

FYI. Superior Shooting (8063239488) has 6XC in Norma / Peterson Lrp / Peterson Srp in stock.
This are all current production and are all extremely good brass. (not the $.30 offering)
A test sample pack of 15 each to see which one you like best is $32.
Peterson (lrp/srp) is $.69 each Norma is $.74 each

I have shot all 3 and each handles high pressure very well. The Peterson is typically 15 fps faster than the Norma which is not much of a difference as speeds over 3200 fps.
If you pick the srp then do some hangfire testing with your small primer pick..

 

[Ben Pickel]

I just bought some of the Peterson lrp from Superior Shooting. I've experienced sticky cases with older lots of the Norma and with the Peterson cases offered by Grafs. To date I've only been able to run fireformed Winchester 22-250 through my rifle for XTC rapid fire strings.

The brass that Mr. Tubb is carrying is good to go. I tested some of the first 100 cases I bought today and it cycled perfectly with no sticky lift. I just bought another 900 cases today after leaving the range. Very happy to have this available.

 

[DarkStar]

My Norma brass (LRP) bought from SSS a few years ago, have been pretty much flawless for feeding/chambering/extraction.

I might give the Petersen SRP a whirl once all the hurricane issues settle down a little more.

In the meantime, given some of the posts and PM's here, I'll run the Alpha brass again (firing #2) with a little less ummph and see if the bolt stickiness goes away.

 

[DTubb]

My Norma brass (LRP) bought from SSS a few years ago, have been pretty much flawless for feeding/chambering/extraction.

I might give the Petersen SRP a whirl once all the hurricane issues settle down a little more.

In the meantime, given some of the posts and PM's here, I'll run the Alpha brass again (firing #2) with a little less ummph and see if the bolt stickiness goes away.

Having HAD head hardness issues in the PAST with initial Norma (2005ish) and initial Peterson production (Graf stuff) the issue has been resolved.

I have been shooting my 6XC with all 3 and see no TUBBGUN bolt lift issue with speeds approaching 3300 fps using 115 DTACs.. Brass shows some pressure signs but NO bolt lift stickiness.

Other 6XC brass makers will likely continue to struggle and recommend an oversize diameter chamber (6XCII) to try to mask the head hardness issues associated with it's production process.

 

[6MMsteve]

the Peterson brass is some good stuff very nice, I looked at some through a Microscope in the Lab last night and it looked just smoochy, primer pockets have a tiny chamfer on them.