6.5 CM 130gr Scirocco Load Data??

[choprzrul]

Swift is telling me to start 0.040" off rifling.

Beyond that, has anyone loaded for this bullet in a 6.5 Creedmoor?

I'm thinking RL17 or H4350

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[choprzrul]

It appears that Norma N-203B is temperature stable, has de-coppering ingredients, and it gives velocity nearly identical to IMR4350 and H4350.

....and.....it just so happens I have 4lbs of it coming from MidSouth

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[Divernhunter]

No Norma data but RL17 looks to be excellentstart40.4grs/2665FPS and max 43.5grs/2893FPS.
IMR4350 also good 41.8grs/2659FPS max 45grs/2844FPS
Nothing in swift manual for H4350

That bullet like jump. give it even more for better accuracy

[elk hunter]

Are you saying that the Swift book COAL of 2.825 is or isn't correct? The norma powder you list is not in the Swift #2 book, a new book?

[elk hunter]

I did a little digging on this topic and here's what I find. The Swift #2 book is revised and does have some new powders. I suspect that there is a industry standard for the chambers and throat dimensions for the 6.5 CM and here's what I find when I checked my new Winchester 6.5 CM. My unscientific methods tell me that the swift bullet will close with feel on a cartridge using the Swift Scirocco 130 gr. bullet and it measures 2.868 so the book OAL of 2.825 is 43 back from the rifling. Here's another tidbit on this subject.

https://www.handloadermagazine.com/swift-scirocco-ii

My conclusion is that the book already builds in that 40 back part. I have used the Scirocco bullet to shoot a elk with and it works. My 300 RUM was shooting very good with those bullets seated at book COAL.HTH

[choprzrul]

After using my Sinclair Bullet Seating Depth Tool, I found my OAL length to the rifling is 2.799"

So....I put together a load ladder using IMR4350 using 2.760" OAL and 1% charge increments. QuickLoad told me 44.4gr was max, but I went a couple increments above that and saw no signs of pressure.

Here is what my raw data table looks like:
Raw Data.JPG

42.4gr
42.4.JPG

42.8gr
42.8.JPG

43.2gr
43.2.JPG

Ironically, I loaded 5 rounds after finishing the ladder, and chose 42.8gr randomly. Here are the first 5 rounds I shot this morning post bore scrubbing and to warm the barrel ahead of testin:
cleaning.JPG

I used Shooter's Choice to remove carbon fouling, and then switched over to BoreTech's CU+ to remove all traces of copper from when I was testing with eTip and TTSX bullets. I used my borescope to confirm there were no traces of copper left.

The action bolts were tightened while pulling down on the barrel/action. Hand snug front and then back, 25 inch pounds front and then back bolts, 35 inch pound front and back, and finally just the front to 40.

All shots were fired from a Blackhawk Sportster Titan FX shooting rest. Once the barrel was just warm, I used a chamber chiller for 2 minutes between shots. I used 12 targets and shot them round robin.

All fps were gathered using LabRadar. All shots were measured at home using calipers and then plotted into PointBlank Ballistics.

So.....no 'node' jumps out at me from the gain numbers. The starting load at 40.8gr gave me a legit one hole clover leaf coming in at .22" However, at 2598fps, I'm questioning its viability as a deer hunting load? If I overlay the 5 cleaning shots, 42.4gr, 42.8gr, and 43.2gr, I get 14 shots coming in at 1.5" or so. Take the one far right shot out, and I have 13 at just under an inch.

At this point, I'm going to wait for my Norma 203B to show up. Quickload tells me that 38.9gr of 203B will make the same velocity as 42.8gr of IMR4350. I will load 10 each using 203B:

38.7gr
38.9gr
39.1gr

.....and see how those groups look. Hopefully they will all be very similar in size and POI. If so, I'll pick the best of the 3 and try 10 more with a 0.020" jump to rifling and 10 with a 0.060" jump to rifling. I will have to check QuickLoad to see if I need to tweak the powder charge to keep velocity the same....

So, what says the CG community? Am I on the right track here? Methinks that Tikka is shooting pretty good for a deer rifle. I hope I can make a minor tweak or 2 and get it down to a solid 1/2" shooter. Better yet if I can keep all 10 at 1/2"

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[LynnJr]

Seating depth is more critical with a secant ogive bullet.
Seating with solids tend to need more jump than thin jacketed lead core bullets.
The steeper the boattail the more important seating depth is to accuracy.

The 130 bullet you are using has all three characteristics so seating depth is where you will see the biggest gain in accuracy.
I would pick the powder charge that you feel had the best chance at shooting small and load up a seating depth test in 0.010 increments from 0.040 off the lands to 0.130 off of the lands.
If you see a spot that shrinks your groups use that as your new baseline and run another ladder test with your powder.
H4350 is a known good powder in that chambering and Fetterly who advertises here has it in stock.

You are going about the process correctly.

[choprzrul]

Seating depth is more critical with a secant ogive bullet.
Seating with solids tend to need more jump than thin jacketed lead core bullets.
The steeper the boattail the more important seating depth is to accuracy.

The 130 bullet you are using has all three characteristics so seating depth is where you will see the biggest gain in accuracy.
I would pick the powder charge that you feel had the best chance at shooting small and load up a seating depth test in 0.010 increments from 0.040 off the lands to 0.130 off of the lands.
If you see a spot that shrinks your groups use that as your new baseline and run another ladder test with your powder.
H4350 is a known good powder in that chambering and Fetterly who advertises here has it in stock.

You are going about the process correctly.

Most excellent and appreciated advice LynnJr!

I was kinda worried since I didn't see single digit velocity increases in the ladder. It was rather linear in nature....???

What are your thoughts on Swift using a pure copper jacket for that bullet with no alloy material? Is it going to copper foul a barrel faster or slower than an alloyed copper jacket?

I was really liking what I was reading on Norma's 203B powder:

1. very good lot-to-lot consistency
2. de-coppering agent built in
3. pretty good temperature stability.

I don't have a link to cite credit, but here is someone's 203B powder testing across a much bigger temperature spread than this rifle will probably ever see:
N-203B.JPG

-->Is it worth giving up the temperature stability and known success associated with H4350 for a powder like 203B if it helps with copper fouling??

I have plenty of H4350 on hand and 4 lbs of 203B on the way...so I'm ok on inventory.

For reference, the rifle needs to be minute of deer to occasionally taking a poke at prairie dogs out in the great plains of Nebraska. 25-90 degrees is probably the extreme boundaries of temps.

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