6.5CM. IMR 4451 & 140g

[Lunchbox27]

Doing a load workup for a new Tikka. Barrel is 20" 6.5 Creedmoor.

Started out shooting the Hornady american gunner 140's and got great accuracy and decent SD so I started the load development with the 140 hpbt match (since I already have a box of 500). When shooting the Hornady american gunner 140's, im getting 2600 fps with my suppressor.

I started at 41.6 grains of IMR 4451 and went up to 42.8. Accuracy was fantastic and the SD from 42.0-42.6 never went above 10... However, velocity was low for these charges. 42.8 grains gave me 2547 fps and was the worst group. Im looking to get closer to 2600 fps like with american gunner. Yes, I understand that with a 20" my velocity will be a good 120-135 fps slower than a 24". Just looking to get a little closer to 2600.

My question is... Should I try and push for the next higher node? Start at 43.0 and go to 43.6? I had zero signs of pressure. All primer/brass looks the same from 41.6 to 42.8, zero flow or lip and no issues with bolt lift. I appear to still have case room left and my oal is only 2.840. Anyone else have to go into the 43's to get the node/velocity they were after?

I have attached a photo of the 42.8 charged brass.

velocity with charges

41.6 - 2453
41.8 - 2468
42.0 - 2489
42.2 - 2495
42.4 - 2498
42.6 - 2515
42.8 - 2546

 

[JoeBUtah]

I don't know man. Chasing 2600 fps from 2550+- is a 2% gain. Admitedly I don't load for th 6.5 Creedmoor, so I can't offer any solid advice; you might just load a few and see if it's really worth chasing. Good luck!

 

[black5.3]

If you are getting good es/sd and good groups i would start on the higher end of the node and make sure the load is consistent with charge variation. Make sure the poi is in the same spot and still producing good groups and maintains the low es/sd... i would settle in the middle of the high node so that your load wont be much affected by weather variations and let it ride. If your getting around 2550 out of a short barreled 6.5 with 140's then you are doing good.

 

[Lunchbox27]

So, 42.2 was my best group at .322". Velocity was 2495, SD 7.8. On each side both 42.0 and 42.4 were 1/2 moa and SD in the 10's, so 42.2 is a solid load. That said, think I might try and find some RL16. I have RL17 but I know its got temp issues.

 

[black5.3]

Thats not too bad.. the sd is ok too.. so your wanting to switch from imr4451 to rl16 now you have about dialed it in?

 

[davere]

In theory, RL16 will yield faster velocities than 4451. I haven't played with it, yet - but I have been working up loads for 140 RDF and 147 ELD-M with 4451 for 6.5CM. In my gun (Stiller TAC30 action with a 24" Bartlein barrel), 43.6 is yielding 2800 fps with a 140 RDF (Hornady once fired brass, CCI 200 primer, .030 off lands). I've loaded up to 43.9, and just start to see pressure signs there.

In a 20" barrel, you might be better off with a faster powder, and maybe even a lighter bullet - but if you figure 150fps slower, then it seems like you could possibly get to around 2650? I don't know 35-40fps per inch of barrel is correct, but...?

 

[Lunchbox27]

In theory, RL16 will yield faster velocities than 4451. I haven't played with it, yet - but I have been working up loads for 140 RDF and 147 ELD-M with 4451 for 6.5CM. In my gun (Stiller TAC30 action with a 24" Bartlein barrel), 43.6 is yielding 2800 fps with a 140 RDF (Hornady once fired brass, CCI 200 primer, .030 off lands). I've loaded up to 43.9, and just start to see pressure signs there.

In a 20" barrel, you might be better off with a faster powder, and maybe even a lighter bullet - but if you figure 150fps slower, then it seems like you could possibly get to around 2650? I don't know 35-40fps per inch of barrel is correct, but...?

Yes, IMR4451 is just not that fast in this barrel/length. I ran a load test today with RL17. My old load in my Ruger precision was 40.6 at 2715/2.8 SD without the Omega can. At 40.5 in this Tikka 20" its 2607/7.7SD with the can. Accuracy was again great through all charges. Im going to run some temp testing with it and see how it fairs. My shooting season is 75-90 degree days since my range closes for the winter months. In the mean time Ill scope out my LGS for some RL16.

 

[Deadshot2]

Your speeds sound awfully slow based on what I'm getting from my 6.5 Creedmoor. 42.2 gr IMR-4451 using Hornady Brass and Fed GMM primers gives my 140 gr ELD-M's right at 2700 fps.

Barrel is a Benchmark 24" 1:8, 3 groove. SD's are consistently in the 3-6 range with ES rarely going above 10. When I use this load in Lapua brass I've reformed from .308 Palma (small primers) the speed jumps to 2775 but SD/ES stays low. Pressures are definitely at the upper limit however with ejector wipes just starting to show.

FWIW, all of my Benchmark Barrels have been fast tubes with speeds running a minimum of 100 fps faster than the barrels they replaced.

Now have a 2-groove on order for my .308 and am anxious to see what it does.

 

[Lunchbox27]

Your speeds sound awfully slow based on what I'm getting from my 6.5 Creedmoor. 42.2 gr IMR-4451 using Hornady Brass and Fed GMM primers gives my 140 gr ELD-M's right at 2700 fps.

Barrel is a Benchmark 24" 1:8, 3 groove. SD's are consistently in the 3-6 range with ES rarely going above 10. When I use this load in Lapua brass I've reformed from .308 Palma (small primers) the speed jumps to 2775 but SD/ES stays low. Pressures are definitely at the upper limit however with ejector wipes just starting to show.

FWIW, all of my Benchmark Barrels have been fast tubes with speeds running a minimum of 100 fps faster than the barrels they replaced.

Now have a 2-groove on order for my .308 and am anxious to see what it does.

For a 20" barrel? The Hornady shot 2600 fps avg, Prime was 2740 avg, Norma match 130 was 2767. Seems pretty close to what others with a 20" are getting with a can. It was just the 4451 that seemed slower in this rifle. Not that Im complaining, I wanted the 20". Was just looking to match the velocity of the hornady and the IMR just fell short.