Primer cups....

CyaN1de

CyaN1de

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Which primer has a thicker cup, CCI BR2 or Federal Gold Medal Match Magnum Large Rifle?

I am piercing primers with the BR2's but I have a couple thousand Federal Magnum Match primers I could try instead. I cannot get any CCI 250 primers at the moment so I am looking for the thickest of what I have until I can get the bolt face bushed.

TIA
Richard
 
I know federal is known for softer primer cups, but I believe most magnum primers use heavier cups hence my question regarding the Federal Mags vs the CCI BR's
 
From what I have heard, the CCI BR2, 200, 250's share a similar cup and they are as tough as they come.??????

If pressure is the main reason, going to a magnum primer is going to make things worse.

Is the firing pin protrusion out of whack - too far out? Easy enough to check, just pop it out of the cam slot. Should be around 50thou with no burrs.

Have you considered going to H4831SC? I saw that you were running H4350. Maybe a slower powder can help.

Load too hot? flattened primers?

Jerry
 
mysticplayer said:
From what I have heard, the CCI BR2, 200, 250's share a similar cup and they are as tough as they come.??????

If pressure is the main reason, going to a magnum primer is going to make things worse.

Is the firing pin protrusion out of whack - too far out? Easy enough to check, just pop it out of the cam slot. Should be around 50thou with no burrs.

Have you considered going to H4831SC? I saw that you were running H4350. Maybe a slower powder can help.

Load too hot? flattened primers?

Jerry
Click to expand...

Flattened primers - some
Hot Load - no
Firing Pin Protrusion - .054

Velocity is 2886 avg with the load I was using. 42.5gr H4350, Bergers seated .015 into the lands
 
Does the problem go away if you use less powder?

Do consider using H4831SC. Slower pressure rise may be all it needs to be happy happy.

I tried H4350 when developing my 6.5 Mystic and didn't like how peaky it was (no problem in other applications). Temp change, whatever and I would get flyers due directly to pressure spikes.

With that jammed bullet, the pressure curve may be too sharp allowing your primers to fail.

I suspect easing off the powder and/or backing the bullet off the lands will resolve your problems. If so, you had a pressure problem.

A 260 rem is only supposed to shooting in the 2700fps with 140's per SAAMI. Of course, we are using magnum type pressures and going faster but you may be too close to the edge.

Jerry
 
I have some 4831SC that I will try as well.

I was hoping to shoot it in Nokomis next weekend so it doesn't give me a lot of time to play with it.

From Hodgdon site:
142 GR. SIE HPBT Hodgdon H4350 .264" 2.780" 41.5 2590 50,100 PSI 44.5 2735 58,000 PSI

I got same velocities with Berger 140's as I did with Sierra 142's
 
CyaN1de said:
From Hodgdon site:
142 GR. SIE HPBT Hodgdon H4350 .264" 2.780" 41.5 2590 50,100 PSI 44.5 2735 58,000 PSI

I got same velocities with Berger 140's as I did with Sierra 142's
Click to expand...

I am sure you barrel is longer then the Hodgdon test barrel but it might be of similar diameter (test bores and match barrels tend to be on the smaller side of spec).

By going to just under 2900fps, you are well over saami spec pressures. SWAG would be around 15 fps per inch of barrel after 26". So if you are running a 30" barrel, I would expect somewhere in the 60 to 75fps gain on barrel length alone.

I wonder if jamming into the lands causes you to see peak pressure sooner and longer?????

If you can find quickload or similar, I bet you will find that you are in the high 60,000psi range. Depending on other factors, you may peak into the 70's?????

That can lead to primer piercing for sure. H4350 will spike in this application and I really didn't like it - very temperamental. H4831SC was way nicer. I doubt my peak pressure is any lower but the curve is likely flatter. My guess is that you will need to run around 44 to 46gr H4831SC in your 260 for a velocity nearer to 2800fps to get rid of any problems.

Although the hodgdon powders are temp stable, they will still react to much warmer temps. If you were testing in the 20C range and go closer to 30C with a load on the edge, you will have lots of fun.

I went the improved route so I could get the extra case volume and thus the velocity without running too close to pressure problems. Most barrels seem to like going 2900/2925fps with my 139gr Lapuas. One is going 2950/3000fps with little fuss.

I hope you can get things dialed in for Sask...

Jerry
 
I was hoping to get to 2950 with it as that seems to be a nice node from what I had read on other sites.

The load I am using is also Ron Hermes load (he uses Sierra) and Terry Chupa shoots the same load in his 260 (Scenar bullets) without issues.

Quickload shows 42.5gr of H4350
99.5% fill
59692 PSI
Vel. 2892

Pretty close to the real world numbers I am seeing on the chrony. Within 8fps.

Maybe I need to turn another .0005 off my necks :(

46gr of 4831SC would put me at 106% fill
Vel 2859
58881 PSI
according to QL anyhow.
 
The big problem with quickload are the assumptions the program must make. Bore varies so much that to get the same velocity, one barrel may be fine, another way too hot. Without pressure trace gear, we will really never know.

But if you get pierced primers with BR2, something is definitely amiss. Bushing will mask the problem but you still have the problem.

I love my Savage and their oversized bolt face hole. You will get cratering with toasty loads (magnum pressures), no ifs ands or butts BUT it is a wonderful indicator of where you are pressure wise. As long as I keep the loads below where there is blanking or other such nonsense, I know my pressures are warm but not silly and my powder is burning in a range that seems to work best (60ishK PSI and CCI primers)

More often then not, I am unable to reach the velocities I read about. Tried various 308's and 223's and they never shot anywhere near the super sized speeds other report. I always ran into pressure issues and/or lousy accuracy. Best accuracy was always in the SAAMI expected speed range.

Sharp shouldered cases seem to be more tolerant of opening up the throttle.

If you can get your groups be nice and tight with no vertical, that would be more important to me then a 100fps more speed and blowing a match cause your gun grenaded.

Would not like to go through what Ron did at last years Farky and his 6BR run way too hot.

Jerry

PS, if you do get your rig to run this fast, keep an eye on brass flow - trimming, neck turning. My 223's require a lot of maintenance. My 6.5 Mystic, haven't trimmed brass yet but I will skim the necks now and then.
 
mysticplayer said:
If you can get your groups be nice and tight with no vertical, that would be more important to me then a 100fps more speed and blowing a match cause your gun grenaded.
Click to expand...

There is the thing as well. This load had a vertical dispersion of no more than 2 bullet widths at 300m, so the load shoots.

As for Ron's issue last year, it only ever happened with virgin brass. He fired same load, same brass (this time once fired), same primers etc... with no issues whatsoever. He is still baffled as to why this would be. LOL
 
Took it out today with 4831SC, Varget and 4350. All testing at 200M

Lapua 308 cases necked and sized to 260 Rem and necks turned to .0135 ish
BR2 Primers
Sierra 142's seated at the lands

Varget - Nothing spectacular.
4350 - No pressure but nothing worth mentioning
4831SC - went from 44g to 46 in .5 increments
44g - 4 shot cluster with 1 shot 1/2" left of the cluster but only 2770FPS
44.5-45.5 open groups. Mirage was getting pretty bad as well so may have something to do with it.
46g had 3 side by side touching and then 2 shots 1/2" above touching. Primers were not flattening so I figured I could hot this up a little bit.

No pressure signs today and no pierced primers...YAY

Went out again this evening to test some hotter 4831SC loads and had some great results in 1x fired brass.

Sierra 142's seated at lands:
46g 4831SC was again 3 side by side touching and 2 shots 1/2" above touching.

46.3g - 4 in a 3/4" group and 1 flyer up and left 3/4" away

46.6g - See Pic
P1030009-r.jpg


46.8g - 1.25" circle of holes






Moly Berger 140's jammed .015

46g - 1" circle of holes

46.3g - See Pic:
P1030008-r.jpg


46.6g - 3/4" "group" 2 in 1 hole in the middle, 1 shot up and left, 2 shots touching low right.

46.8 - My first 3 shots of this load were in one .540" (Outside-Outside measurement) hole and I thought this was going to be "THE" load, then the next 2 shots went up and right and were .742" apart (outside to outside, .314 inside to inside) and 1/2" up from the other 3 :( I will be retesting this load though on Wednesday) Velocity for this load looked like it should have been in the low 2900's but the light dimmed quite a bit and the chrony was getting errors and reading low as the load before it (46.6) was at 2891fps. Avg of four shots recorded was 2851fps?!?!?!
 
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I think I figured out my pressure problem....neck wall thickness. I believe the walls were not turned enough which was enough to cause the pressures I was seeing.

Took 4350 out again after making sure necks were all the same and proper thickness. Pics speak for themselves:

All bullets were Sierra 142 seated at the lands
BR2 Primers and H4350 for powder.
All were 5 shot groups.
All were shot at 200m in zero conditions.
God I love our range from 19:00 on :D

44grn of powder with Virgin brass (light fireformed with pistol powder and CoW to iron out neck shoulder junction)
Yes...thats 4 shots in 1 hole at 200m!!!
I will be trying this load again as I had less shoulder on the gun for the high shot.
44grn-BR2-4350-Sierra142atlands.jpg


44grns of powder with 1x fired (full load) brass same load as above.
44grn-BR2-4350-Sierra142atlands-1xF.jpg


43.5grns of powder with Virgin brass
Looks like I took some of the backer board home with me. :D
435grn-H4350-BR2-Sierra142atlands.jpg
 
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