Pressure issues reloading for Christensen

[Lazyace]

I've got a Christensen in 6.5x284, 26" bbl. that I started working up hunting loads for. The problem is that I experienced very high pressures approaching max loads. Very tight bolts and extractor marks on cases. Those were still only at 2800-2900 fps. I've tried RL22, RL25 and 4831SC with both Berger 140 and 156 gr. Elite Hunter and Fed 215 primers. I spoke with Berger and they said that Christensen barrels and actions had very tight tolerances and most people had to adjust down to starting loads. The folks at Christensen are no help at all.

I've cut my loads and came up with the best accuracy being 47 gr. of 4831SC but now I'm only pushing 2575 FPS. My COAL is 3.275 which I think is about .035 off the lands. Question is, what can I do to get more velocity while staying away from the pressure issues? This rifle should easily shoot 3000 fps, but i can't get close. I'll be using this for LR elk and mule deer. Out to 800 yards.

 

[AudentesFortunaJuvat]

I'd check out RL-16 or RL-26, both good powders that gave me best velocity in my 6.5 creedmoor, 2720FPS out of a 22" proof sendero with 42.2 grains RL-16 seated .090 off. Unfortunately both are hard to find right now. I'm seeing RL-26 push 180gr VLD from a 7SAUM at about 3030fps.

Sort of sounds like a different issue, something other than powder choice. I'm concerned that your guessing how far off the lands you are. If you are in fact seating to be into the lands, that could be your pressure, maybe your setup wants to be jumped more/less.

i would recommend getting the Hornady gauge or using the chambering method for determining your max CBTO so you have a defined measurement to work with. Then follow Berger's seating depth testing process outlined on their website to determine your optimal seating With a safe charge. Work from there on the powder choice and charge. Stick with one bullet so bearing surface is constant and you aren't affecting your charge or potentially crushing powder with the 156.

just my .02, take it with a heap of salt as I've only been reloading my Creedmoor 2 years, still lots to learn.

 

[RockyMtnUT]

I've got a Christensen in 6.5x284, 26" bbl. that I started working up hunting loads for. The problem is that I experienced very high pressures approaching max loads. Very tight bolts and extractor marks on cases. Those were still only at 2800-2900 fps. I've tried RL22, RL25 and 4831SC with both Berger 140 and 156 gr. Elite Hunter and Fed 215 primers. I spoke with Berger and they said that Christensen barrels and actions had very tight tolerances and most people had to adjust down to starting loads. The folks at Christensen are no help at all.

I've cut my loads and came up with the best accuracy being 47 gr. of 4831SC but now I'm only pushing 2575 FPS. My COAL is 3.275 which I think is about .035 off the lands. Question is, what can I do to get more velocity while staying away from the pressure issues? This rifle should easily shoot 3000 fps, but i can't get close. I'll be using this for LR elk and mule deer. Out to 800 yards.

There has been quite a few issues with their chambers. It is being discussed on another group right now. The results have been chambers that are inconsistent. Not sure,other than at first most were saying the ammo was the issue but later determined bad chambers that had to be sent back multiple time to get them to fix. It was not and isolated incident either. The rifles were blowing out primers and heavy ejected marks.

 

[twister]

Whats your neck diameter of a fired round? There have been some thick necked batches of Lapua brass that i need to turn.

 

[Sockeye66]

I do think the assurance of exactly where the bullet is from the lands would be where I would start to make sure you're not starting off jammed. Maybe even get a box of some quality factory ammo, at least you'd have some fire formed brass and see if the pressure signs are still there. H4831sc is a known powder for the 6.5x284 in accuracy with decent velocity that isn't unpredictable although I shoot RL23 in mine. That said, Sickbuild sounds like he knows of inherent issues with those rifles and it certainly could be that as well.

 

[rammac]

I've got a Christensen in 6.5x284, 26" bbl. that I started working up hunting loads for. The problem is that I experienced very high pressures approaching max loads. Very tight bolts and extractor marks on cases. Those were still only at 2800-2900 fps. I've tried RL22, RL25 and 4831SC with both Berger 140 and 156 gr. Elite Hunter and Fed 215 primers. I spoke with Berger and they said that Christensen barrels and actions had very tight tolerances and most people had to adjust down to starting loads. The folks at Christensen are no help at all.

I've cut my loads and came up with the best accuracy being 47 gr. of 4831SC but now I'm only pushing 2575 FPS. My COAL is 3.275 which I think is about .035 off the lands. Question is, what can I do to get more velocity while staying away from the pressure issues? This rifle should easily shoot 3000 fps, but i can't get close. I'll be using this for LR elk and mule deer. Out to 800 yards.

3000 FPS "easily"? I don't think that you're being realistic. Long range competition shooters are pushing the high end and they seem to be sticking to 2885 to 3050 FPS in custom barrels that are mostly longer than 26 inches using the lighter 139 to 142 grain bullets.

6.5-284 Cartridge Guide

6mmBR.com is the best guide for 6mm BR Benchrest precision shooting, complete with 6BR FAQ, Reloading Data, Shooter Message Boards, Reader Polls, and Photo Gallery. Match event calendar and rifle competition accuracy training tips. Equipment reviews (.243 bullets, 30BR cartridge, 6mm Norma...

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If the long range competition shooters are pushing those kinds of speeds in their custom barrels then I'd bet that a commercially produced rifle with a tight chamber (based on who knows what bullet profile) would produce signs of high pressure at those same velocities. Your using a different brand bullet and that will have an effect on the chamber pressure when you are pushing the top end.

 

[Lazyace]

Whats your neck diameter of a fired round? There have been some thick necked batches of Lapua brass that i need to turn.

The fired rounds are.292-.294. I'm sizing with Hornady Match dies and the .289 bushing. Lapua brass.

 

[Lazyace]

3000 FPS "easily"? I don't think that you're being realistic. Long range competition shooters are pushing the high end and they seem to be sticking to 2885 to 3050 FPS in custom barrels that are mostly longer than 26 inches using the lighter 139 to 142 grain bullets.

6.5-284 Cartridge Guide

6mmBR.com is the best guide for 6mm BR Benchrest precision shooting, complete with 6BR FAQ, Reloading Data, Shooter Message Boards, Reader Polls, and Photo Gallery. Match event calendar and rifle competition accuracy training tips. Equipment reviews (.243 bullets, 30BR cartridge, 6mm Norma...

www.6mmbr.com

View attachment 216966

If the long range competition shooters are pushing those kinds of speeds in their custom barrels then I'd bet that a commercially produced rifle with a tight chamber (based on who knows what bullet profile) would produce signs of high pressure at those same velocities. Your using a different brand bullet and that will have an effect on the chamber pressure when you are pushing the top end.

Yes, at loads of 50-51 gr. I was getting a lot of pressure with both 140 and 156ngr. Bullets. Maybe not 3000 but I just wanted to get more out of it than 2575 with 47gr.

 

[Lazyace]

There has been quite a few issues with their chambers. It is being discussed on another group right now. The results have been chambers that are inconsistent. Not sure,other than at first most were saying the ammo was the issue but later determined bad chambers that had to be sent back multiple time to get them to fix. It was not and isolated incident either. The rifles were blowing out primers and heavy ejected marks.

What page is the other group discussion on?

 

[twister]

The fired rounds are.292-.294. I'm sizing with Hornady Match dies and the .289 bushing. Lapua brass.

you might need to neck turn. thats not leaving much space if your brass is .014 if bigger that will give you pressure.

h4831 in my couple gives me 2950/60 or so with 140's and 2830/50 with the 156 with R26. those are both custom too.

If the gun has a tight bore the RDF bullets should help a bunch.

 

[Dmagna]

I've got a Christensen in 6.5x284, 26" bbl. that I started working up hunting loads for. The problem is that I experienced very high pressures approaching max loads. Very tight bolts and extractor marks on cases. Those were still only at 2800-2900 fps. I've tried RL22, RL25 and 4831SC with both Berger 140 and 156 gr. Elite Hunter and Fed 215 primers. I spoke with Berger and they said that Christensen barrels and actions had very tight tolerances and most people had to adjust down to starting loads. The folks at Christensen are no help at all.

I've cut my loads and came up with the best accuracy being 47 gr. of 4831SC but now I'm only pushing 2575 FPS. My COAL is 3.275 which I think is about .035 off the lands. Question is, what can I do to get more velocity while staying away from the pressure issues? This rifle should easily shoot 3000 fps, but i can't get close. I'll be using this for LR elk and mule deer. Out to 800 yards.

Send it back! I had the same issues. The barrel is junk. I had the same rifle.

 

[Dmagna]

I am having mine rebarreled with a proof barrel because Christensens are junk.

 

[Dmagna]

Don't waste your time and frustration with it. Also never tell them you shot reloads, it's always factory ammo. They will void your warranty.

 

[Shane Lindsey]

I have a 300 RUM. It's from when they still used Rem 700 actions and screwed on their barrel. I get pressure signs below book loads. Christensen barrel is going down the road.

Waiting on a Carbon Six now...