.22 Creedmoor - sudden pressure spike

[chris101]

Hoping someone on here might have been here before....

I have a .22 Creedmoor rifle, a Tikka T3x, rebarelled with a Bartline 7.7" twist, 26". From new last year I shot around 170 home loads, no issues excellent accuracy using Hornady 75gn ELDMs, new Alpha SRP brass, Reload Swiss RS62, MV around 3650ft/sec. BTW, I always shoot this rifle with a suppressor.

So come 2 days ago I bring it out to check the zero with the remainder of the same ammo, the rifle has not been used for a few months now. MV is slightly higher than last time by 50/60ft/sec but that may be because its a much warmer day than the last time I chrono'd it, almost "hot" for the UK.

Anyway, accuracy still great, but the bolt lift is HEAVY, ejector swipe on brass, but primers OK. After another few shots I stop and move onto a lighter loading (1.5gn less), bolt lift is still heavy, too heavy. So time to stop and clean. Used the usual solvents, C4 for the carbon and KG12 for the copper. Got the bore scope out, lands are clean, still some carbon streaks in the grooves for the first 8 to 10".

The solvents just aren't shifting this, so time for some gentle use of JB bore paste on an oiled patch, maybe 15/20 short strokes where its needed. Barrel looked cleaner but not been scrubbed to death as I've read all the Bartlein comments about not using abrasive pastes.

Barrel solvent flushed, chamber degreased. Tried my usual loads this evening, STILL getting heavy bolt lift but maybe not quite as bad, brass still imprinting on the bolt face.

Thoughts? More JB until I hit bare metal and strip out all the carbon?

Just seems amazing that what must now be fairly light fouling can cause such an issue.

 

[ctrickett]

IMO its coppering up very fast, causing high pressure. I had it happen with a 6xc barrel, I'd fire 20 shots, after that cant lift the bolt, primers coming out.....NOT a hot load (38.0 H4350 105 bullet) that particular barrel brand never worked for me, no issue in many other barrel brands.
It could a twist rate for your barrel....I know nothing about 22 Creed except a friend was blowing up bullets due to RPM's in a 6.5 twist

 

[FoxTales]

Used RS62 on and off for a few years , never really had a problem with copper deposits . If I recall the camfor coating was supposed to make the powder more temperature stable and reduce copper fouling . I noted the latter doesn't appear on current blurb . The quality control was also questionable a few years back and one of my loads lost 100fps when using a new batch . I should add , I've always been a little over zealous with my cleaning regimes .

If the barrel is scoped and clean , check for fouling in the chamber . I'm not trying to teach you to suck eggs here , apologies if it comes over that way .. If it's a new batch , chrono it .

When my rifle returns from the smiths in 22 CM , RS62 ready . My RS62 has seen service in 243 , 270 , 6.5CM and 6XC without issue , could be just cleaning as the OP and @ctrsuggest .

 

[mic2377]

The likely reason your bolt lift is heavy is your load is HOT. If you velocity was 50 fps greater than your original work up velocity of 3650, that means you are launching 75's at 3700. That is 250-350 fps more than published max loads depending on source, although your barrel is a touch longer.

For frame of reference I run a 80 ELDX at ~3250 out of a 24" barrel. Yes I have tried a bit higher, but accuracy/consistency was much better at these speeds, and there legitimately are no pressure signs to speak of. The barrel is a 24" 1/7.5 twist Shilen.

 

[Gary in MD]

Yup, another one that is loaded too hot....

 

[chris101]

Yes indeed, these are hot. Tried some test loads at 3500f/s last night and still heavy bolt lift. Backing down to 3450f/s and will try again later. Shame because it was producing one hole ragged groups at 100yds @ 3650f/s.

Funny thing was that there were no pressure signs previously, so I guess a combination of higher temperatures and carbon fouling has reached a tipping point.

 

[urbanrifleman]

Yes indeed, these are hot. Tried some test loads at 3500f/s last night and still heavy bolt lift. Backing down to 3450f/s and will try again later. Shame because it was producing one hole ragged groups at 100yds @ 3650f/s.

Funny thing was that there were no pressure signs previously, so I guess a combination of higher temperatures and carbon fouling has reached a tipping point.

Super temp sensitive powder.

 

[FoxTales]

The likely reason your bolt lift is heavy is your load is HOT. If you velocity was 50 fps greater than your original work up velocity of 3650, that means you are launching 75's at 3700. That is 250-350 fps more than published max loads depending on source, although your barrel is a touch longer.

For frame of reference I run a 80 ELDX at ~3250 out of a 24" barrel. Yes I have tried a bit higher, but accuracy/consistency was much better at these speeds, and there legitimately are no pressure signs to speak of. The barrel is a 24" 1/7.5 twist Shilen.

There's no available data on Reload Swiss 's website at present , they do usually respond quickly to any questions regarding data . An email is in order , I'll post their response if no one beats me to it .

 

[FoxTales]

I like to keep my word and a hat tip to Dominik at Reload Swiss, here's the data he provided for the 75grain ELD-X.

Please read the caveats on the upper page !

 

[linebaugh]

Had this with carbon ring issues. Bore paste was my friend

 

[mic2377]

Interestingly enough, the data provided by Reload Swiss mimics the velocities I noted above as a reasonable target (3250 +/- 50 FPS) for a reasonable pressure (55k) load.

It seems there is an internet tendency to chase higher and higher velocities. The inevitable sequelae of this (short brass and barrel life, inconsistent accuracy, etc) is masked somewhat by the access we have to sturdy actions and really good/hard brass. The signs are there if you really look though.

From brief extrapolation with the above data it suggests your hot weather velocities of 3650-3700 are likely the result of 75k+ psi pressures.

As for me I will continue to use moderate loads that don't beat up the brass or rifle, and provide consistent performance without blowing anything up even if it gets hotter outside.

~just a boring guy whose velocities are not even worth bragging about

PS the other suggestions to stay on top of cleaning, and rule out a carbon ring, are also very salient for an overbore cartridge like the 22 CM

 

[xswanted]

Hoping someone on here might have been here before....

I have a .22 Creedmoor rifle, a Tikka T3x, rebarelled with a Bartline 7.7" twist, 26". From new last year I shot around 170 home loads, no issues excellent accuracy using Hornady 75gn ELDMs, new Alpha SRP brass, Reload Swiss RS62, MV around 3650ft/sec. BTW, I always shoot this rifle with a suppressor.

So come 2 days ago I bring it out to check the zero with the remainder of the same ammo, the rifle has not been used for a few months now. MV is slightly higher than last time by 50/60ft/sec but that may be because its a much warmer day than the last time I chrono'd it, almost "hot" for the UK.

Anyway, accuracy still great, but the bolt lift is HEAVY, ejector swipe on brass, but primers OK. After another few shots I stop and move onto a lighter loading (1.5gn less), bolt lift is still heavy, too heavy. So time to stop and clean. Used the usual solvents, C4 for the carbon and KG12 for the copper. Got the bore scope out, lands are clean, still some carbon streaks in the grooves for the first 8 to 10".

The solvents just aren't shifting this, so time for some gentle use of JB bore paste on an oiled patch, maybe 15/20 short strokes where its needed. Barrel looked cleaner but not been scrubbed to death as I've read all the Bartlein comments about not using abrasive pastes.

Barrel solvent flushed, chamber degreased. Tried my usual loads this evening, STILL getting heavy bolt lift but maybe not quite as bad, brass still imprinting on the bolt face.

Thoughts? More JB until I hit bare metal and strip out all the carbon?

Just seems amazing that what must now be fairly light fouling can cause such an issue.

Running a rifle in the 85,000 pounds of pressure, you'll probably get some stiff bolt lift when the temp rises.

Before you lose an eye or three, I'd back this bad boy down a few grains.

 

[chris101]

71,000 psi according to my now recalibrated Quickload, dropped down to 3450f/s which should be under SAAMI max now, and after a deep clean all is good again.

 

[hogpatrol]

Another thing to check is the brass length. I go .005 shorter than reamer spec.

 

[FoxTales]

For anyone who may be interested the other data I requested .
From Dominik at RS .. again, please read caveats.

 

[NZ_Fclass]

There's many reasons that I don't use double base powders. Thankfully, in NZ we don't have the REACH regulations and I can currently get Varget, H4895 and H4350 (AR2206H/08/09) to my hearts content. I would suggest to the OP that, as you have Vihtavouri N160 available ... .Alliant 26 is available here, at twice the price of AR2209 ( that's another reason).

During the shortages of a few years ago, I was forced to switch to IMR4166, but kept the loads in a low pressure mode to avoid pressure spikes and heating. I still use the 6BR barrel and the Norma brass from that year. The small amount of 4166 remaining, I use for fireforming 6BRX cases.

 

[FoxTales]

There's many reasons that I don't use double base powders. Thankfully, in NZ we don't have the REACH regulations and I can currently get Varget, H4895 and H4350 (AR2206H/08/09) to my hearts content. I would suggest to the OP that, as you have Vihtavouri N160 available ... .Alliant 26 is available here, at twice the price of AR2209 ( that's another reason).

During the shortages of a few years ago, I was forced to switch to IMR4166, but kept the loads in a low pressure mode to avoid pressure spikes and heating. I still use the 6BR barrel and the Norma brass from that year. The small amount of 4166 remaining, I use for fireforming 6BRX cases.

What would the OP gain from N160 that he isn't getting from RS62 ? They're both single base !
Just curious about your train of thought .

 

[NZ_Fclass]

What would the OP gain from N160 that he isn't getting from RS62 ? They're both single base !
Just curious about your train of thought .

My mistake. I assumed that as an Alliant Powder that it was double base. I just checked the Swiss website - which i should have done before posting.

 

[FoxTales]

My mistake. I assumed that as an Alliant Powder that it was double base. I just checked the Swiss website - which i should have done before posting.

No problem, I'm guessing you got mixed up with RS60 /Reloder 17 which is produced by Nitrochemie(RS).
My understanding is Alliant and RS have an agreement not to sell both in the same marketplace as they're the same product .

Is the RS range available over in NZ ?

 

[NZ_Fclass]

No problem, I'm guessing you got mixed up with RS60 /Reloder 17 which is produced by Nitrochemie(RS).
My understanding is Alliant and RS have an agreement not to sell both in the same marketplace as they're the same product .

Is the RS range available over in NZ ?

Only as Reloader 26. I have a half pound which I "inherited". Haven't tried it yet. I could probably try to duplicate the "Carolina Load" in the Creedmoor ay some point