6PPC-USA, Higth Speed/Accuracy

B

BERGEON

Guest
Hello,

I'm a French shooter and I began in the 6PPC-USA with my Savage 12VLP “Improved” with à Whidden V-BLOCK, the Action is a Savage 12 VLP with a Bolt Head PT&G PPC Familly. My barrel is a BORDER Cutrifled, bore .237''; 24’’- 14’’.

Last Sunday , I test ten loads (26.4 gr +0.3 gr to 29.1 gr N133) in my Savage “Improved” 6PPC-USA whit the BERGER 68 gr FB (Moly) +Fed GM 205M + NORMA Case 6ppc-usa the better Load is this:

small12.jpg
(with wind at 100 m)

I was very surprised because the better load is the one who make the more speed 3 312 fts in my barrel…(those Norma cases are very good!) Is it à problem for the live of my Barrel ?

Best regards.

Laurent.


.
 
Thanks Lee Martin, for these reassuring details!

I use NORMA case 6PPC-USA and for this first load with 29.1 gr N133, I was surprised to see more soot on my the shoulder case!

dscn6810.jpg


I will think with this hight load (bullet touch the land) the FireForming will be total ??? Is it right?

A+

Laurent.
 
My BORDER need high speed for accuracy !!!

I recently buy some BERGER 65 gr BT but the seating depth with my new BERGER 65 gr BT in order to touch the land! And I was surprised because I have only .055’’ into the case neck whit this BT, certainly less than I normally use with my 68 gr FB…

I used my N133, but this powder need more neck tension ( more over .002''!) and my only solution is to increase the neck tension is to use a Bushing more tightening!

For resizing my neck cases to work with this BT, in my chamber (Reamer JGS N° 1261 6MM PPC SAKO; Neck .270'' ) I use a Bushing .261’’ to increase more neck tension for fight this little engagement in my case neck! My outside neck diameter (NORMA Case) of a loaded round (Berger 65 gr BT) is exactly .264 17’’

With my NORMA case (Factory to use "No Turn Neck!") and my chamber with .270’’ Neck , I know the clearance is to much about .006''…

Last Sunday (with wind at 100 m) I test seven loads (27.3 gr +0.3 gr to 29.1 gr N133) in my Savage “Improved” 6PPC-USA whit the BERGER 65 gr BT (Moly) +Fed GM 205M + NORMA Case…

I was very surprised because the most accurate loads is still that which develops fastest speeds!!! (29.1 gr N133 /3378 fts)

The accuracy at 100 m whit this BERGER 65 gr BT is exactly the same with the BERGER 68 gr FB/ 29.1 gr N133 (3312 fts) ???

I don’t understand because, I don’t try accuracy loads under high speed in my BORDER (24’’ length, twist 14’’) indifferently using those two bullets!!!

Please, can you explain me this strange result ?

A+
Laurent.
 
Different barrels can tune very differently. The loads that you describe as fast are not really exceptionally so.

Once when I had seen a shooter shoot a number of .0xx groups in a hundred yard agg. I asked him about his barrel. He told me that it was a well worn cut barrel that only shot well with very slow loads. Ask you barrel what it likes, and then feed it accordingly.
 
Boyd Allen said:
Different barrels can tune very differently... Ask you barrel what it likes, and then feed it accordingly.
Click to expand...

Yes, I was surprised with my BORDER chambered in 6PPC-USA who work well with only speed loads because I have another BORDER chambered in 243WIN and is work as well with slow loads as some speeds loads...

I was wondering where could come this difference of tolerance in those tow barrel?

I was I measured the inside diameter of my two barrels ( grooves diameter and lands diameter) look at the results :

243 WIN (after 624 shots)
- Bore diameter = .243 11'' (6.175 mm)
- Groove diameter = .237 60" (6.035 mm)


6PPC-USA (0 shot)
dscn6212.jpg

- Bore diameter = .242 71'' (6.165 mm)
- Groove diameter = .237 40" (6.030 mm)

My 6PPC-USA groove diameter is thin than my barrel chambered in 243 Win!

Is this thin diameter can explain my 6PPC barrel likes the speeds loads?

A+
Laurent.
 
I have another question about my two different necks cases after shots...


I use two cases in my chamber (Reamer JGS N° 1261 6MM PPC SAKO; Neck .270'' )

-With NORMA case ( Factory to use "No Turn Neck!") The loaded round mics 0.264 17" at the neck! The clearance is so bigger ! .005 82 ''

-With LAPUA .220 Russian, with my Neck .270'' I turn the LAPUA Neck to have the loaded mics .267 32'' and with those LAPUA cases the clearance is .002 67''


Can you tell me if the difference of clearance is the results of my two necks cases after shot ?(I think I have a real problem of seals with of my NORMA Nek...)

-NORMA Case 6PPC-USA "No Neck Turn" (load 29.1 gr de N133). -LAPUA case .220 Russian Neck Turn (FireFormed load 25 gr N133).
collet10.jpg
collet11.jpg



Or Norma brass is harder than Lapua brass?...Can you help me please?

A+
Laurent.
 
BERGER Bullet Stability Calculator

I read this morning this article :

http://bulletin.accurateshooter.com/2015/03/how-ballistic-coefficent-varies-with-twist-rate-stabilization/

I have doing just good tests with my BERGER 65 gr BT in my barrel 1:14'' and I want to look the result of this bullet in the Berger online calculator :

65_gr_10.jpg


I don't understand I have a good accuracy with my gun and this bullet (100 m)!
dscn6813.jpg


And the calculators tell me : The bullet is unstable.Expect bad accuracy, tumbling bullets, and keyholes in targets !!!

The more surprised is the "Minimum Twist stability recommended " is 1:11'' then this bullet is recommended to Berger "For 1 in 13" Twist or Faster"!!!

I don't understand more...

I will doing my future test at 300 m whit this 65 gr BT... I'm afraid to look some tumbling bullet in my target Now!

A+
Laurent.
 
Forgot the stability calculator. The PPC has shot beautifully with 1:13 - 14 for decades. Some guys have gone as low as 12, some as high as 15 and depending on the bullet length, they print. I like math, but when the real world bucks equations, I go with real world results.

-Lee
www.singleactions.com
 
Lee Martin said:
Forgot the stability calculator. The PPC has shot beautifully with 1:13 - 14 for decades. Some guys have gone as low as 12, some as high as 15 and depending on the bullet length, they print. I like math, but when the real world bucks equations, I go with real world results.

-Lee
www.singleactions.com
Click to expand...

Dusty Stevens said:
Looks like if they tumbled they flipped a perfect 180deg
Click to expand...

Boyd Allen said:
+1
Click to expand...

Thank you gentlemen for your reassuring views!

This morning I test this BERGER 65 gr BT at 300m she's work very well think, so do I ...
28_8_g10.jpg
(mY better load at 300 m! 28.8 gr N133 V0=3323fts)
(I mail to Bryan to ask him this very strange result...)

A+
Laurent
 
Wind Flag...

Hello,

I looking for to buy wind Flag...I interesting for Orlando's wind flags!

Please can you tell me about your experience with these wind flags?

A+
 
I seen an orlando mini flag on a bench one time but past that ive never seen one at a centerfire benchrest match. Most of us use smileys flags
 
Different parts of the country, different flags. Out here, I see a lot of Rick Graham's flags, and propellers (commonly called daisy wheels) have become a lot less common. His materials and workmanship are excellent. http://www.brflags.com/
 
Round spring loaded ejector pin Mark = Hith presure ???

Hello,

I'm a little frightened!!!

I have this ejector groove mark in my case :

trace_10.jpg


29.1 gr N133/ BERGER 68 gr FB (moly): Fed GM 205 M

V0 for 5 shots max: 3391 fts
mini :3347 fts

Is this mark are the result of high pressure? Because the primer is good!!!

Thank you for your help!

A+
Laurent.
 
Nice, high-resolution picture. Yes, you are extruding brass into the ejector hole. The 6PPC experts can correct me if I am wrong, but I believe Norma brass is softer than Lapua. So a load that would work fine with Lapua brass might not with Norma. Yes, the primer looks OK.

Are there any benchrest shooters around Amiens?

Cheers,
Keith
 
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