300 WSM x RL23 x 180 Scirocco II

[Laguna Freak]

After experiencing my 0.058” to 0.061” leade accuracy node with 62.5 gr RL16 load that was 0.4 moa at 100 yd, open up to 1 moa at 200yd (1.5+ moa at 300 yd) and not come back in with loads up to heavy bolt lift at 64.7 gr, I decided to work with RL23.

In conducting 200 yd RL23 ladder tests and watching for pressure signs, while trying to conserve my precious components, I found the long leade was not performing satisfactorily and went back to square 1 at 0.015” leade. I may have ID’d two velocity nodes that are 0.3 gr +\- wide. They are loads 4, 5 and 6,7 on the target.

The only load that potentially indicated pressure was load 7 but it also was a bit resistant in chambering which I thought was due to inadequate shoulder bump / my error. The case head shows a slight scratch and their was a shaving of brass on the crf extractor claw.

I’m curious if some of you 300 WSM x RL23 afficionados can offer some sage counsel on whether it is worth the expense to test higher charge weights or not with the inherent strain on brass and the diminishing downrange terminal ballistics ROI. Or would you work seating depth in these 2 potential velocity nodes? This is out of a 24” barrel.

Thanks in advance for sharing your experienced opinions.

 

[Orr89rocz]

Fwiw my 180 berger elite hunter in norma brass runs 68.5 gr with 215M primer, gets 3063 fps from a 24” barrel. Set at max mag length of 2.97” which jumps it like over .120” i think. Cuz the base to ogive is 2.235”. With a 210 VLD set at 2.97 oal and 2.285” base to give, i see lands at 2.405” so im jumping those .120, and they shoot really well

i would play with rough seating changes at this point with either of those nodes. 4/5 or 6/7. Maybe try one at 68.2-68.5 to see if theres pressure

 

[Joe Salt]

For one your to hot, I'm only shooting 65 Gr. with a 204 gr. bullet and your using Winchester Brass.
You must be using a long drop tube to get that much RL-23 powder in the case.

Joe Salt

 

[Orr89rocz]

68.5 was basically up to near the neck shoulder junction for me. No drop tube. I also have shot 65.3 with a 210 but my accuracy node has been with 64 gr with the 210 vld

 

[Joe Salt]

Go for the accuracy not the speed.

Joe Salt

 

[Laguna Freak]

For one your to hot, I'm only shooting 65 Gr. with a 204 gr. bullet and your using Winchester Brass.
You must be using a long drop tube to get that much RL-23 powder in the case.

Joe Salt

Hey Joe. Thanks for the reply. No drop tube. I’m pretty sure the Scirocco II is not even touching powder. Though I maybe mistaken. I’ll check that out.

Lighter charge weights were not grouping satisfatorily. Don’t have my book handy but I started at around 63 grains originally and worked up to 67 in half-grain increments. Then reduced to 0.2 gr increments. No real pressure indications aside from what I mentioned above which I’m not yet convinced was a pressure issue.

Btw; I only have about 1 year experience with the Swift SII but everything I’ve read about it in handloads promotes pushing it hard for best accuracy performance. Of course, there are limits.

 

[Laguna Freak]

Fwiw my 180 berger elite hunter in norma brass runs 68.5 gr with 215M primer, gets 3063 fps from a 24” barrel. Set at max mag length of 2.97” which jumps it like over .120” i think. Cuz the base to ogive is 2.235”. With a 210 VLD set at 2.97 oal and 2.285” base to give, i see lands at 2.405” so im jumping those .120, and they shoot really well

i would play with rough seating changes at this point with either of those nodes. 4/5 or 6/7. Maybe try one at 68.2-68.5 to see if theres pressure

Thanks for sharing this^^^. I was wondering if another 0.2 +\- gr might bring the higher node over to center. I’m just not sure I want to stress my brass that much. Oddly, recoil is not bad on any of these loads and I’m not a big guy.

Do you have an opinion on my brass scratch from the info provided in light of your personal experience?

 

[Orr89rocz]

Sorry i have nothing to add to the case marks other than this... I have noticed sometimes on a hard to chamber round the bolt will mark the case head. Like a swipe. My 257 rob is tight headspaced and my sizing die doesnt really bump shoulder back, if it does its only .001. I find it sometimes harder to close bolt on them but they shoot great. But if i close bolt and open (not firing it) sometimes theres a swipe on the case head. So it wasnt pressure.
Maybe revisit it, try a round or two at that powder weight and see if it is sticky or get more marks. Be safe with it. But you might have something going with 4/5 or 6/7 with seating depths. Idk if getting to 3000 fps is going to happen or if it’s necessary if accuracy is good.

 

[Willow]

I run 65gr of RL23, pushing Berger 215gr bullets. Norma brass, S&B primers. This gives me 2900fps out of a 31" barrel and accuracy is outstanding. Norma brass is holding up ok and the waterline at 800 metres is flat.

 

[Matches]

What is a 0.058 to 0.061 leade accuracy node?
Is it your seating depth?

 

[Laguna Freak]

What is a 0.058 to 0.061 leade accuracy node?
Is it your seating depth?

Yes. It was with RL16.

 

[Matches]

I am running 64 grains of H4350 under a 190 grain bullet and 66 grains was still fine.
My reamer has 0.287 freebore so more than a factory chambering.

 

[Laguna Freak]

For one your to hot, I'm only shooting 65 Gr. with a 204 gr. bullet and your using Winchester Brass.
You must be using a long drop tube to get that much RL-23 powder in the case.

Joe Salt

Hey Joe,

I finally got back to working on this load. I loaded 2 each at 67.4, 67.5, 67.6 grains. The RL23 powder level is in the shoulder region. Pretty much at the bottom of the shoulder at 67.4 gr and well shy of the neck at 67.6 gr. No drop tube.

Based on a somewhat widely used rule of thumb of 1 gr powder variance per 10 gr bullet weight, and my own experience, I’d say this 180 Scirocco II load is comparable to your 204 gr bullet load with regard to pressure potential. It may be a bit hotter at 67.6 gr but is showing zero indications of being over-pressure.

Here’s a Pic of the bullet at seating depth 0.015” off lands which is the jump used in the target image above. Bullet is still below the shoulder and is touching powder but not near as far as it was with my RL16 load.

 

[Orr89rocz]

Sounds about right. Like i said my 180 berger load is 68.5 in norma brass. Its warm but shoots great, mainly cold weather shooting but even in warm air it hasnt seemed to bad at all. No heavy bolt, primer looks ok to me. No ejector marks

 

[Laguna Freak]

I think this demonstrates the limit of my ability today.
Load = 67.5 gr RL23. MV = 2990 to 3002 with temp @ 86 to 90 F and humidity from 65% to 41% when finished. It took me about 1.5 hrs to shoot 3 at 200 move the target, reset chrono and shoot 3 at 300. Third shot low & left at both distances. Guess I did not allow enough cool time between 2nd and 3rd shots. I know I was hovering a bit left at fire of 3rd 300 yd shot.

Highlight = 200 yd
White = 300 yd

 

[Laguna Freak]

Incidentally the ES on the first 3 rounds at 200 was 3 fps. 3000 to 3002. Seems a bit odd that the other 3 spread 2990 to 2998.

 

[Orr89rocz]

Hmm maybe try a tenth or two grains up and down, or abit of seating variation, couple thousandths. I have read two shots close 1 off may like decreasing OAL.

 

[Laguna Freak]

Hmm maybe try a tenth or two grains up and down, or abit of seating variation, couple thousandths. I have read two shots close 1 off may like decreasing OAL.

Good ideas. I’ve been 0.003” both sides already. But may try less and more later if the loose nut on the trigger proves to be “not the problem”. I can work with what I have for this month’s bear hunt. If I need more than one, I’m good. If I need more than two, I’ll be plenty pist at the loose nut on the trigger.
I get pretty triangles from 67.4 to 67.6 gr. 67.5 at top-center.

 

[Laguna Freak]

WY Black Bear season was over before I left TX. That just meant I didn’t take any rifle other than my defense rifle on our 5.5 week trip.

I finally got back out to the range today to shoot this 67.5 gr load 4 rounds at 300 yd again. It started off great with the first 2 shots spread 0.14 moa. I’m still scratching my head on shots 3 & 4. I’m suspecting the culprit is the loose nut behind the trigger. There was some mirage at 72 F bright and sunny and the 300 yard target is back in the trees so it was shady but no shifting shadows. Wind was R - L @ 4-7 mph.

MV= 2993
3022
3013
3007

 

[INTJ]

If you are shooting from a stable rest, then shots 3 and 4 were not due to shooter error. I see this all the time when a good barrel doesn't like a load. If your rest isn't stable and the crosshairs aren't dead steady when you pull the trigger, then you may need a better rest setup.

While RL-23 is always the first powder I try in a 300 WSM, not all barrels like it best. Some like H4350 or IMR 4451 when RL-23 or H4831 SC won't work.

Your barrel just may not like Sciroccos either.

The classic load for a Berger 215 in a 300 WSM is around 64.5 grains of RL-23. Usually gives 2900 fps in a 29-30" barrel. My current load for my BR rig is 62ish grains of IMR 4451 with the Berger 215s, also at around 2900 fps.

In my lighter weight hunting rifle in 300 WSM, 24" barrel, it likes 64ish grains on H4350 with Barnes 168 TTSXs. Pushes them to about 3050 fps.

My thought is you need to make a bigger change to tighten up your groups.