Powder residue entire length of case....help

[hop700]

Out shooting this morning with new Savage LRH 6.5x284. I was looking for a starting point so I tried 3 different loads/bullets.

new lapua brass
r22 50gr
CCI 250
OAL approx. 3.100 (throat of barrel still has .200" free bore). I chose this length so that all bullets would have 100% neck contact (namely the VLD).

#1 140gr Hornady SST. shot pretty well, around MOA. Slight extractor mark on some cases.
#2 140gr accubond. Shot pretty well, just under MOA Slight extractor mark on some cases.
#3 140gr VLD. Only shot twice due to powder residue on outside of case all the way to the base.

I do not believe these loads are over pressure. Primers are not flattened and no heavy bolt. I will take a look when I clean the gun to see if there is a burr around extractor slot as I believe this may be the culprit to burnished heads.

I stopped shooting the VLD's when I noticed the residue. I would guess that I'm under pressure and not sealing the chamber. Has anyone seen this before?

Are the Lapua cases hard (they do come with necks annealed)?

Thanks in advance
Scott

 

[Gene]

Virgin brass and light loads may be your problem. You did not say what your loads were. When I fire new virgin brass, I want a load with pressures around 50,000 psi. That will firmly fit the brass to my chamber and force the case head against the bolt face.

Some shooters have reported that excessively light loads can cause action blow ups. I cannot verify that.

 

[hop700]

Thanks Gene. I was using 50gr R22 (Berger book suggests 49.0 - 51.8), with CCI 250.

I think I will try 50.5 ans 51 to see if the problem goes away. If it persists I will work on the 140gr AB as they shot around 3/4" 5 shot group. Maybe the new LR accubonds will shoot better once available!

Scott

 

[hop700]

FYI: temp was around 30 degrees.

 

[varmintH8R]

That is a weird deal - I've never had an issue like that. To Gene's point, it sounds like a poor case/chamber seal. Can you measure headspace and case diameter on the virgin brass versus fired (especially w/ the Hornadys that didn't have the issue)? Maybe it will show something??

If you determine the cause please post it - always interested in solutions to issues I'll probably have some day.

Good luck!

 

[hop700]

VarmintH8R,
I'm running the cases thru a redding (B-series, expander) neck sizer to uniform mouths as they are dinged due to shipping. FYI: I did not like the initial work the expander was doing so I took the die apart and noticed the usual burrs, stoned and polished to remove. I took a few measurements:

Headspace using Hornady gauges:
Fired 3.845"/3.844"
Loaded unfired 3.837"/3.836"
Looks like about .007" - .009" gap. Would this be considered excessive for such a sharp shouldered round?

Neck OD:
Fired .2967" - .2965"
Loaded .294" - .2938"
After necking .2929" - .2925"

Scott

 

[varmintH8R]

Hi Scott,

Disclaimer first - I am not a pro, so my experience is just that - practical experience. I will always defer to the pros. That being said:

I don't shoot 6.5-284. To get a frame of reference, I went and checked what virgin and fired brass I have on hand. I did some measuring (hornady headspace gauge also) and found:

300WSM, Winchester M70, Winchester cases, insert E
Unfired: 1.735" to 1.736"
Fired: 1.738"
Max spread: 3 thou.

22-250 rem, Cooper M54, Winchester Cases, insert B
Unfired: 1.561" to 1.563"
Fired: 1.565"
Max spread: 4 thou.

Based on that, the headspace change you are seeing is greater than the two different cartridges that I have on hand are showing. Excessive? I am flat-out not qualified to answer that. As you are using Redding dies, I would reccommend shooting them an email - my experience with their tech service has been great.

As an aside, I got into shooting/reloading 280AI a year or so ago. I was doing some research as Nosler standardized (through SAAMI) this chambering so they could market brass and ammo. I was considering buying some brass to save the effort of fire-forming. What I found is they had reduced headspace by 14 thou vs the original PO ackley design. Thus, their brass is 14 thou short in an original PO ackley chamber. Based on what I was reading, shooters/reloaders considered 14 thou "free" headspace excessive and a safety concern for case stretching / case head seperation. As a frame of reference you may want to Google it and see what they say as well.

 

[hop700]

VarmintH8R,
Good idea, I did a little searching and found head space issue which prompted me to measure OAL on cases. This is weird:

New brass very consistent at 2.160"
Hornady fired = 4 cases did not stretch 2.160", 1 stretched to 2.165"
Nosler fired = 5 cases all stretched to 2.165"
Berger fired = 2 cases did not stretch 2.160"

I'm just not sure how hard Lapua brass is but would hint toward low pressure hard brass.

I have a local gunsmith that I will contact tomorrow to see if we can run go - nogo gauges into the chamber.

Scott

 

[varmintH8R]

Makes sense to me. Let us know what you find out!

 

[jpnicho]

When I had that problem, a pro told me to anneal the necks. After he showed me the tricks to annealing, that fixed it. He anneals necks every 4th loading.

 

[DocB]

Great Thread Guys!! I'm a rookie also so all this builds my 'data bank'. Thanks for sharing your experiences, trials and tribulations! Very much appreciated

Doc

 

[hop700]

jpnicho - I definitely think there is some relevance here, this is why I ask about the hardness of the Lapua brass even though they are annealed from the factory.

I cannot get out until this weekend but I intend to load a few vld's at 51grns. I'm also contemplating extending the OAL, though hesitant because I want 100% neck contact due to using this load for hunting (mostly for target but hunting nonetheless).

I will follow up.
Scott

 

[Bullet bumper]

It can also be too light neck tension. If the powder is slow and the load light the bullet gets out before the case neck seals.
With new Lapua cases I doubt that neck hardness is the issue .
Try a tad faster powder or higher neck tension .

 

[hop700]

Bullet Bumper, I agree, this could also contribute to the cause. More neck tension - more pressure.

I believe the problem was due to low pressure. We could add neck tension, increase overall length, but I elected to increase powder charge. Today I shot 3 loads at 51gr of R22 and the powder residue was contained to the neck area only! I will not shoot more of these loads until I get a chrono to shoot across. I feel there are too many variable at play and fps is a critical piece of the puzzle that is missing.

Thanks to everyone who contributed. I MAY post my final findings but I'm sure it will be a long time down the road as I want to do this right and.......did I mention the 270WSM/300WM/22-250/223.......!

Regards
Scott