6.5 PRC & 156 EOL (Work up thread)

[SteveBurton]

Make sure you check your headspace with a stripped bolt before you start bumping shoulders or you'll make it worse.

 

[vancewalker007]

I spent today doing some work on a load for my 6.5 PRC. I started with groups of 3 at a charge I was comfortable with.

ADG virgin
N565
CCI 250

3x 2.165 CBTO
3x 2.135 CBTO
3x 2.105 CBTO

I then determined 2.135 would be my start point based on target.

I then loaded the following

55.8 - 56 - 56.2 - 56.4 - 56.6 - 56.8 - 57 - 57.2 - 57.4

I was getting some crunch on 57.2 and I elected to stop at 57.4

Back to the range:
2791
2806
2791
2820
2827
2839
2845
2878
2877
View attachment 349052View attachment 349053View attachment 349053

I am new at this point but I think I see faint ejector marks at 57-57.4 but bolt operated fine. I tried to capture what I am seeing but maybe it's not coming through.

Questions:
Would you keep pressing for more fps?
Do you see concerns with these spent primers?
Any data spots jumping out on my ladder(55.8 and maybe 57.2 look interesting to me)?

I have a reference point on some custom ammo I was shooting last year. 2769fps and a CBTO 2.137. But I kinda want more juice:
View attachment 349054

Thoughts/opinions

At 2877fps you'll still be 1600+ fps at 1000 yards at 500 ft alt, and just gain fps as you go up in altitude. You should gain some using RL26. You will gain some from N560 as well. Its closer to RL26 in burn rate. You might break 2900fps before hitting pressure. I'd run a powder ladder and find your rifles pressure point with RL26. I'd use 0.2 gr increments and stop when you get to a load that causes a heavy bolt lift.

With the limits of components these days I'd just load up single rounds with a safe lands distance, say 40 - 50 thou off for the ladder. Then, take velocity on each shot. I bet you break 2900 pretty easy. It's too bad you have such a short throat. Thats robbing some performance.

I'm able to run a 2.3995 CBTO and still be 15 thou off the lands so I have a lot of case left. I need to re-measure as I'm sure my throat has moved a little. With 58.2gr of H1000 and 2 more inches of barrel I can safely get 3040fps, likely even more if I had some RL26 to play with. I've been shooting this load for over 3 years now. I think you'll find the 156 to be very accurate and its devastating on game. I've shot little stuff like Coues and Springbok up to Sable and Eland with it.

 

[Reemty J]

Vance walker now there is a testimonial " coues to eland "

 

[jpndave]

I ran this for a buddy the other day. You can see theoretical relative speeds. This is Hornady brass and again, theoretical but I have found the comparisons between powders are generally pretty close. VV570 is your fastest in both PRC rounds.

Same run but RL565 was off the bottom of the page so this is just that data but more powders.

 

[JD Jones]

It's too bad you have such a short throat. Thats robbing some performance.

Can you help me understand this a little better? I was thinking the performance was being robbed by the magazine restriction.

 

[BrentM]

I ran this for a buddy the other day. You can see theoretical relative speeds. This is Hornady brass and again, theoretical but I have found the comparisons between powders are generally pretty close. VV570 is your fastest in both PRC rounds.

View attachment 349569


Same run but RL565 was off the bottom of the page so this is just that data but more powders.

View attachment 349570

I don't know why exactly but the slower powders like 565, 568, and retumbo don't produce the results as expected. The short fat case seems to really shine with 26, 560, and h1000 burn rates.

 

[vancewalker007]

Vance walker now there is a testimonial " coues to eland "

Same rifle.

 

[BrentM]

Can you help me understand this a little better? I was thinking the performance was being robbed by the magazine restriction.

I doubt you're being robbed of anything. Guys running long actions aren't getting much of any performance benefits over short actions. Where the is potential for gains is 2 fold: 1. Using a large kernel slow burn powder and fill rate is such you have to compress the charge heavily. Couple of issues there for sure. 2. Seating the bullet too far off the lands if the bullet design is not forgiving of jump. For example old designs where short jump to jamming was the only way to get accuracy.

Today, you have better powder choices and bullet designs that are not nearly as critical so you can get away with a lot of old school no no's. You can easily jump bergers .75-.200 and see excellent results. Old design was -.005-.010 when I started using them.

 

[WYO300RUM]

What would you expect out of the 156 with retumbo? Velocity and grains of powder? Wyo300

I think you'd be able to get more Retumbo in the case. I maybe wrong. Possibly higher velocity. I can't tell you what either would be.

 

[WYO300RUM]

I must have a pretty slow barrel. 24" PRC with 156 EOLs in a mid-length action. I start to see mild signs of pressure at:

H1000 - 2802
N565 - 2833
RL26 - 2836
Retumbo - 2861

I've found super accurate loads with each powder so accuracy hasn't been a problem, just not seeing velocities commonly shared. If I stick with this bullet, the best combo for me is looking like 57.2gr of Retumbo at 2840fps. At this point, I'm working up with 140VLDs. Not sure the 156 juice is worth the squeeze for my ranges.

Try Berger 153.5 ot Nosler 142 LRAB

 

[WYO300RUM]

What primers have you tried? I was seeing pressure signs early with magnum primers.
I've had 2 barrels on my CA. The original Ridgeline CF barrel didn't give me the velocity that others saw. Now I have a CarbonSix barrel on it and I still see others posting higher velocity. I don't know how they are squeezing as much powder as they're posting into the case (Gunwerks/ADG). If I loaded the same amount, the powder would be spilling over. I'm going to be happy with the 2880fps I'm getting with the 156s.

I start getting some pressure after 56 grs. RL26 in ADG/Gunwerks brass. But I'm getting 2921 fps w/156.
W/124 Hammer and RL23 I'm getting 3200 something. 3240 I think.
Fed 210 match were best. Lower ES and SD than CCI BR2

 

[Don Spence]

I am shooting A 6.5 STW 156gr Berger getting 3250 fps
R26---- 77.4 gr Its a Killer

 

[WYO300RUM]

Lot more powder but that's awesome. I'm shooting a 215 Berger at 3240.

 

[Wachsmann]

Well it's been a few trips with bullet length seating changes, different power charges and BR2's with star line brass, I finally got the gun shooting decent. I just need to shoot again without the chrono attached. Generally in the past this hasn't made a big difference since the barrel is a bull barrel. I'm only loading 45 grains of RL26 getting 2760fps average for 5 shots. Next plan is load up some more and then try and true it out to 1000y. According to the app I should be at 1679fps and 977ft/lb of energy at 1000. The brass would not shoot 46 grains without pressure. 45.7 was max but still made the bolt lift a little sticky. I believe my final seating depth was 2.955 for COAL. Should do the trick for some mule deer this fall.