Loading 6.5 PRC to CM speeds

[Megalodong]

Wanted to see if anyone has recommendations on powders or even just feasibility of this.

Wanting to get a double duty rifle I can shoot NRLH comps with but also take backpack Elk hunting.

Any chance I can run the 156 or 153.5’s down around 2700 from a 22” barrel and have good accuracy and SD? Main worry I think is case fill.

I have a 21” 6.5 PRC right now that I’m going to try some test loads out of. I have H4831SC, H4350, H1000, N565, N570, and Retumbo.

 

[Dogtown]

This is what Quickload is perfect for. Here I've set the cartridge, bullet and 21" barrel, then asked it "give me a list of powders that get this combo to 2700 fps"

Lots of options there for you. In situations like this, let Case Fill % & Propellent Burn % help drive your decision.

 

[acourvil]

It seems doable to me. I shoot the 153.5s in a 28” barrel with a moderate load of H1000 at just about 3000fps. I think once you adjust for barrel length and maybe drop the load a grain or 2, you will be right in the ball park. I don’t see H1000 on the list above, but it should be in between 4831 and Retumbo.

 

[Dogtown]

H1000 looks too slow

 

[acourvil]

Interesting. Seems odd to me, since Retumbo is slower. And I think there might be something wrong with the fill % number, I don’t think 54-55 grains is a compressed load. But I do see Holden has 55gn of H1000 listed as a max load for a 153gn ATip bullet, so I guess my load might be hotter than I thought.

 

[Dogtown]

Quickload is predictive and not ground truth, so only use it as a ballpark guide, not gospel.

 

[acourvil]

Understood. It might have something to do with the brass; I’m using ADG brass with a H2O volume of 68.3, other brass might have less volume. But when I first started out with the 6.5 PRC, I tried Retumbo in some loads and got less velocity than with H1000, so that was part of why it seemed odd to me.

 

[Dogtown]

Maybe...here's the default case capacity QL uses for 6.5PRC

So if I plug your value into QL and run it for H1000...

...and Retumbo

Notice that when they're both at 100% case capacity, H1000 still gives you a bit more velocity

 

[acourvil]

O.k., that looks more like what I would have expected.

Back to the OP‘s question, looks like 4831sc or H1000 might work (depending on brass capacity), and for the shorter barrel I would probably try the 4831sc first. Not sure about the VV powders, I don’t have much experience with them.

 

[straightshooter1]

O.k., that looks more like what I would have expected.

Back to the OP‘s question, looks like 4831sc or H1000 might work (depending on brass capacity), and for the shorter barrel I would probably try the 4831sc first. Not sure about the VV powders, I don’t have much experience with them.

I recently got ahold of some 4831sc to try for the first time and based on what I'm getting in my 6.5 PRC, it's not a good fit . . . mainly because of low case fill bumping up against max pressure. It's an excellent powder for non magnum cases, like .243 Winchester. H-1000 would be better.

Running the 156 or 153.5-grain bullets at 2700 fps from a 22" barrel is feasible. You might want to experiment with powders like H4350 or N570 for good accuracy and low SD, considering case fill. Testing loads with your existing 6.5 PRC barrel is a great starting point.

H-4350 has the same problem as 4831sc. N570 can work, though it's a little the oppose of H-4350 in that a full case barely gets one to the upper velocities one might be after. N565 works much better (lol, assuming one can find any ).

 

[wade2big]

Everyone on the Hide are loading 6.5CM to 6.5 PRC speeds. Completely opposite of what you are wanting to do. If you ain’t pushing a 140gr to 2900 fps out of a 22” CM then you haven’t been taking advice from the men here. Nobody that logs on can help you.

 

[Schütze]

Everyone on the Hide are loading 6.5CM to 6.5 PRC speeds. Completely opposite of what you are wanting to do. If you ain’t pushing a 140gr to 2900 fps out of a 22” CM then you haven’t been taking advice from the men here. Nobody that logs on can help you.

Your Sarcasm in a reloading forum may not be noticed by a new reloader…and therefore could be quite dangerous?

 

[gunsnjeeps]

Not knocking your question since a .30-06 can be reloaded from .30-30 velocities up but what is the advantage to slowing down the PRC when you already have zeroes and data from known ranges?

 

[IdahoRenegade]

Not knocking your question since a .30-06 can be reloaded from .30-30 velocities up but what is the advantage to slowing down the PRC when you already have zeroes and data from known ranges?

I can't speak for the OP, but I followed this thread because I had the same question. My thought would be if the PRC were "downloaded" to CM velocities, could you match CM barrel life and low recoil, maintain the same accuracy, but still have the option for "hot" (normal?) loads for extreme ranges, windy conditions or hunting. Just a thought-not sure how practical it is.

 

[Top O' Texas]

It would help knowing what capacity your cases/brass is as to adjust for/in ql.

 

[supercorndogs]

It would help knowing what capacity your cases/brass is as to adjust for/in ql.

It helps to read the thread. Post #7

 

[Top O' Texas]

It helps to read the thread. Post #7

That only supports your inputs. I haven't seen what capacity his cases have nor stated.

 

[supercorndogs]

That only supports your inputs. I haven't seen what capacity his cases have nor stated.

Could you please make your answers in the form of intelligible sentences and complete thoughts?

 

[Top O' Texas]

Could you please make your answers in the form of intelligible sentences and complete thoughts?

Still not an answer regarding the op

 

[supercorndogs]

I see. Its been 4 months with no responses to this thread by the OP. I would guess he already got what he needed.

 

[Overclok79]

It seems doable to me. I shoot the 153.5s in a 28” barrel with a moderate load of H1000 at just about 3000fps. I think once you adjust for barrel length and maybe drop the load a grain or 2, you will be right in the ball park. I don’t see H1000 on the list above, but it should be in between 4831 and Retumbo.

Out of curiosity, what charge weight and COAL are you using? I'm struggling to fit enough H1000 in the case to get the 153.5s to 3000 FPS and still fit within mag length. 59 gr of H1000 at a 2.950" COAL only get me 2950 fps out of a 28" barrel and its a crunchy load.

 

[acourvil]

My load is 57.2 of H1000, OAL is about 2.95 (I measure BTO, OAL varies a little). Also a 28” barrel, I guess mine is a bit faster than yours. If yours is a new barrel, it may speed up. IIRC, mine picked up about 100fps from 0 to 200 rounds.

 

[Megalodong]

Sold my 6.5 PRC before getting to do any testing.

Primary use as stated in the OP was a NRLH competition gun. Wanted to run the Bergara MG Lite, but shelling out $3,000 would be a lot easier to stomach if it could also pull double duty as a hunting gun, hence the PRC question. Save some barrel life, less recoil, etc.

I changed direction with the Seekins PH2 NRL offering coming out, as I can get it in 6CM which qualifies for factory division. Also picked up a CDG action I'm getting a barrel in 300 PRC for. So probably not saving any money like I had intended, but gets my needs filled.



If I had stuck with the 6.5 PRC I actually would've probably abandoned the question at the beginning of this thread anyways and gone with a lighter bullet pushed faster. I think ultimately that would've benefited the find/range/engage comp format better giving me more error in the ranging department. Think the 135 Atip going ~3000 fps.

 

[45-90]

Your Sarcasm in a reloading forum may not be noticed by a new reloader…and therefore could be quite dangerous?

Sarcasm?...Some are pushing the 6.5 CM to 3000 fps with 150 gr SMK in factory 24" barrels, with excellent accuracy...but Not in brass cases.
That would be dangerous.

 

[Schütze]

Sarcasm?...Some are pushing the 6.5 CM to 3000 fps with 150 gr SMK in factory 24" barrels, with excellent accuracy...but Not in brass cases.
That would be dangerous.

I know, I’ve read about your experiments. It’s also quite dangerous for you to publish them imo.

One of these days a rifle may blow up on you.

You pretend that you can judge the real pressures without any pressure test barrel, that’s all I need to know.

Do your thing, I have nothing against it but what is the point of promoting it?

Ever thought about that there maybe a reason the components, especially the cases you use have been disassembled again?

Again, completely your freedom to do this. But your posts create copycats despite your warnings….

 

[kthomas]

Sarcasm?...Some are pushing the 6.5 CM to 3000 fps with 150 gr SMK in factory 24" barrels, with excellent accuracy...but Not in brass cases.
That would be dangerous.

And I thought my 140 load going 2830 fps out of a 24" barrel may be a tad too close to pressure.

150's at 3000 fps is madness. Or a typical load on the Long Range Hunting forum.

 

[R_A_W]

For people trying to download a PRC... I had some very terrible SDs/ESs downloading with H1000 in a 25"bbl

153.5 Hybrids, 210M, H1000, unfired Lapua, 10 shots each
53.40gr 2685fps SD12.6 ES48
54.08gr 2720fps SD19.8 ES50

Charges above 56gr tightened up, SDs in the 4-8fps range

 

[45-90]

I know, I’ve read about your experiments. It’s also quite dangerous for you to publish them imo.

One of these days a rifle may blow up on you.

You pretend that you can judge the real pressures without any pressure test barrel, that’s all I need to know.

Do your thing, I have nothing against it but what is the point of promoting it?

Ever thought about that there maybe a reason the components, especially the cases you use have been disassembled again?

Again, completely your freedom to do this. But your posts create copycats despite your warnings….

It's not for the novice, that's why I said it's dangerous, with brass.
But correctly sized and neck turned brass hybrid cases it works and is an option for many who care to go there...and quite a few do.
I have several thousand hybrid cases, and from them into 6 5 CM, 308 Win, 8.6 Blackout bolt gun, 358 Win.
Besides the US military who uses them in machinguns, at full 80,000 psi, for several years, but rumor has it bumped back to 70,000 psi to 75,000 psi preserve barrel life, on full auto.
There is Bruce Thorm at Bat Machine and the maker of Alpha brass running super high pressures on Ultimate Reloader "308 W to 300 WM velocities do not try this at home," on video look it up for entertainment purposes.
They were pushing over 100,000 psi in the Bat action.
I don't do that,.. but they are with this new Alpha brass and Bat actions.
The hybrid cases are rated for operating at 80,000 psi, but mine are limited to 70,000 75, 000 psi max, according to QL the gestimate software.
The majority are held at 65,000 psi in 8.6 blkout 6.5 twist...not the 3 twist ...it builds pressure for a 3 grains lower max on those roughly rifled 3 twist barrels. I do not recommend the 3 twist barrel.
There are alot of new developments and cartridges, some can be greatly improved upon without going to magnum cases...although that's the easy button for most.
I run AR 10s at 62,000 to 65,000 psi max.
A standard load is 2853 to 2865 for 150 SMK 24" AR 10 6.5 CM with Lapua brass
There are alot of options, for those who want less performance or those who want more performance. Never go where you are uncomfortable, and always work up to loads printed anywhere.
I work on a fair of wildcat cases where little or no data is available. Like the 510 whisper...how much powder are you going to put behind that 750 gr bullet for a sub or super load? I now have lots of data on it from just shooting it, and working with QL.
Same with the 8.6 Blackout 6.5 twist, making the 8.6 versitle, as well as accurate, and not dangerous to shoot at supersonic velocities showing a better way to go, than those with the poor quality 3 twist Faxon barrels.

 

[Megalodong]

How does one get into this hybrid case, 80k psi, reloading game? Write up for dummies somewhere??

 

[45-90]

How does one get into this hybrid case, 80k psi, reloading game? Write up for dummies somewhere??

It's already been "wrote up" on this site...I have explained it and re explained many times to individuals.
I have posted and helped guys with obtaining cases, sizing techniques, neck turning, and annealing.
American Reloading has been getting some fairly large batches in but they run out of stock from time to time...but are usually on sale, ...fairly cheap. Alot of guys seem to using these cases.
Used sensibly they are capable of improving standard caliber short 308 sized case heads cartridge performance.
An individual choice as to whether or not its for you.
But if you already shoot hot max brass loads, one can utilize hybrid cases for extra safety, at the lower pressures of your top hot brass loads, as the SS hybrid case heads will easily take that pressure.