N120 in .20 practical, too fast?

[liasis33]

Hi all, new to .20P & to the forum.

Just finished a build in 20P & have a 40gr vmax & N133 velocity ladder waiting to go.

A "gun show conversation" with another .20 cal shooter recommended 8208 & N120 as "other" powders worth picking up. I dont know what to think of this 2# of N120 i jumped on & now have, as it seems to burn & spike kinda quick, and doesn't fill the case well. I've got my suspicions, despite finding limited 223 rem data for it.

I'd welcome some experienced wisdom from the .20 community.

It's a 26" with a 1:10 twist... and I'm hoping to see 4000 or better with a 32gr vmax. I'd also like to keep my fingers & rifle intact while trying to get there.

Is it worth trying to utilize this N120 or should I save it for a 221 FB I wasnt planning on building?

Thanx in advance for any input.

 

[jepp2]

It's a 26" with a 1:10 twist... and I'm hoping to see 4000 or better with a 32gr vmax.

You can get there, but if your goal is to see those 32 gr bullets leaving at 4000 or more a 204 Ruger is a slightly better alternative. I have been above 4,000fps with my 20P but I don't see any advantage to living there, YMMV.

However, that said I tried to help other 20P users by providing doing some load development for both 32 gr and 39/40 gr bullets. I listed load data I found on the 20, 204R and 223 since they are close in water capacity. Some of the published load data for 20P is very hot, well above SAAMI pressures. I had several powders and experience to choose from. My goal was to calculate the powder loading for a 50K psi pressure. You could add in the N120 data available to get an idea of where to start. Much more online data is available for the 32 gr bullets, very little for the heavier ones.

So here is the load summary and the development I did.

 

[liasis33]

Jepp,

Thank you for that invaluable collective. Its rolling off the printer right now.

I put my 40gr break in / velocity ladder together with N133 based on that 6mmBR data... while eyeballing that 3900 fps that 6mmBR claimed.

Maybe I've got a case of "as the internet advertises" expectations for the .20 cal. You seem to suggest you've found a happy spot below 4000.

My real concern with the N120... and reason for the post... is saftey.

N120 seems to have a preference for higher pressures and leaves a significant amount of free space in the 223's 30gr (average) capacity case. I'm under the impression that free space in a cartrige usually calls for a slower cooking powder.

I was hoping someone had already pioneered the N120 in .20p / .20t... or could give me sound evidence on whether or not it's worth attempting. I can find data in 20VT, 222 & 223 for it. Nuthin in 204R, 20T or 20P.

Thanks again for posting a copy of your homework. Very appreciated.

 

[Tommie]

Rather than all the mental gymnastics why not trade your N120 for something more suitable?

 

[liasis33]

Tommy,

That's actually the plan. With the load data jepp shared, (real world results vs the internet's hot-rod data)... I plan to shelf the N120 for either a trade or a different project down the road.

Thanks for helping out.

RP

 

[searcher]

I had experimented with Accurate LT32 (also a fast powder) maybe ten years ago in the .20 Practical and found it to be a wonderful powder. Since then and having tried a plethora of other powders, my own experiences with several firearms always came back to the faster powders providing the best overall accuracy in each rifle. I have not tried N120, though the burn rate is right in the ballpark of H322, Reloader 7 and H-4198, all of which will do OK to pretty good in my own experiments, depending on rifle and bullet. Since you make note of poor case fill - if the case fill is below the shoulder junction - I'd probably not use it at all. If it closely approaches the bottom of the neck, and lead-free or 39 Blitz king or 40 V-Max were used - there would not be much empty space left and deviation may be fine. I shoot a lot of pull-down military powder in a particular 223 varmint rifle which is a REALLY light load, so much so that I get a lot of carbon buildup and poor case fill. Still, I have shot many thousands of rounds of it because it puts them in one ragged hold with that particular rifle - and nothing else tried will. I'd move up the ladder slowly (not more than 2/10th grain increases at a time) which will build you up around 40 fps (more or less) per step. I always go up till I either find accuracy or unacceptable pressure. Even after finding good accuracy - I'll take it up another 1 1/2 grains minimum to see where the top is - then back down as I don't want surprises on a hot afternoon. If I find pressure before accuracy - I abandon the powder. Good luck.

 

[liasis33]

I had experimented with Accurate LT32 (also a fast powder) maybe ten years ago in the .20 Practical and found it to be a wonderful powder. Since then and having tried a plethora of other powders, my own experiences with several firearms always came back to the faster powders providing the best overall accuracy in each rifle. I have not tried N120, though the burn rate is right in the ballpark of H322, Reloader 7 and H-4198, all of which will do OK to pretty good in my own experiments, depending on rifle and bullet. Since you make note of poor case fill - if the case fill is below the shoulder junction - I'd probably not use it at all. If it closely approaches the bottom of the neck, and lead-free or 39 Blitz king or 40 V-Max were used - there would not be much empty space left and deviation may be fine. I shoot a lot of pull-down military powder in a particular 223 varmint rifle which is a REALLY light load, so much so that I get a lot of carbon buildup and poor case fill. Still, I have shot many thousands of rounds of it because it puts them in one ragged hold with that particular rifle - and nothing else tried will. I'd move up the ladder slowly (not more than 2/10th grain increases at a time) which will build you up around 40 fps (more or less) per step. I always go up till I either find accuracy or unacceptable pressure. Even after finding good accuracy - I'll take it up another 1 1/2 grains minimum to see where the top is - then back down as I don't want surprises on a hot afternoon. If I find pressure before accuracy - I abandon the powder. Good luck.

Thank you searcher.

I've done alot of successful reloading, and this current rifle is my second self-barreling / headspacing project. I have had great luck following the notes of all that have gone before me & strayed not from the published twice & three times data... At least until now, as this is my first wildcat venture.

Taking into consideration you powder fill suggestion, (to the shoulder / below the neck)... i wonder where to start with a charge.

I've got published Hornady data for N120 pushing a 40gr .224 vmax starting at 19.5 thru 21 gr max.

I also have .222 rem pushing 45 gr .224 pill with 16.5 thru 18.2gr max.

No luck finding a .20 tac load using N120.

For the purposes of determining a case fill measure only at this point... care to speculate a starting load weight?

I also have a brick of 450s on hand. I've read that folks prefer the magnums... not just to prevent slam fires but also to overcome / stabalize ES issues with lower case fills. I've not tried this yet. Still kinda cautious with the "less chartered territories".

Thanks again all providing input. It's extremely appreciated.

 

[SBS]

Quick Load shows 22.0 gr. of N120 in a 20-223 or 20 Tac with a 32 V-Max produces 3857 fps in a 26" bbl. at 54,745 psi with 96.6% case fill. The is with a 2.165 OAL cartridge. Quick Load is usually pretty close, but loads will vary a little with different lots of powder, brands of cases and various primers, plus overall length and freebore, as we all know. It is one of my preferred powder for the .20 VT, along with RL-7.

 

[SLAYIN'SWEDE]

I use N133 in my 20 practical for 32's and 40's, you'll get 4000+ no problem with 32's.
N120 is my favorite in my 20 VT

 

[liasis33]

Quick Load shows 22.0 gr. of N120 in a 20-223 or 20 Tac with a 32 V-Max produces 3857 fps in a 26" bbl. at 54,745 psi with 96.6% case fill. The is with a 2.165 OAL cartridge. Quick Load is usually pretty close, but loads will vary a little with different lots of powder, brands of cases and various primers, plus overall length and freebore, as we all know. It is one of my

 

[liasis33]

SBS,

Thank you for that QL data. That provides some confidence in doing a load work up.

I have found a lot of .20VT fans using N120... and because of that... looked high & low for a 20 tac or 20P work up someone posted, but with no luck. That's the closest info I've found. Very appreciated.

 

[liasis33]

I use N133 in my 20 practical for 32's and 40's, you'll get 4000+ no problem with 32's.
N120 is might favorite in my 20 VT

Slayin'Swede,

I've got my first velocity ladder ready to go in N133, pushing vmax 40s. Starting at 22.5 & going to 24.5.

I picked up 2 boxes of vmax 32's, and bought the N120 based on a strangers recommendation along with the intention of conserving my tough to find N133.

In times of primer/powder availability I would probably of used N133 exclusively, based on all the positive feedback and abundance of data.

I'm curious to your charge weights for your loads if you dont mind sharing.

For what its worth... when/if I use N120 loads for the break in on this build I'll

 

[liasis33]

... I'll be sure to post the results, share the data.

Thanks again for all the help

 

[liasis33]

Well, I want to thank everybody for their input. I went to the bench with all the advice and... ultimately, the N120 starting weight of 19 grains stopped about 1/4" to 3/16" short of reaching the case shoulder. 22 grains as QL data provided might of reached the shoulder... but I wasnt starting at 55k+ psi.

Just seemed to be alot of "case-space" compared to the almost compressed load N133 gave me. Maybe im over-cautious? First wildcat syndrome? Kinda baffled that Hornady 10th edition has a .223 starting load of 19 gr of N120 for a 40 grain pill.

In the end, I wound up producing 2 ladders:

22.5 thru 24.5 gr of N133 pushing 40s with a 2.200 COAL and 24.0 thru 25.5 gr of N133 pushing 32s also with a 2.200 COAL. My thoughts are if I dont run into pressure at the 24.0 / 24.5 load with the 40s, surely the 24.0 with a 32 gr could be a safe starting point without covering ground (or burning primers & powders) twice.

I'll add photos of those case fills. Again, big thanx to everybody.

Rp

 

[hogpatrol]

Depending on barrel length and bore tightness, anything over 24.5 grains of powder may not be burnt or burnt efficiently. Four 20Ps and I have never gone over 24.3 of N133 in any of them with any weight or brand of bullet.

 

[liasis33]

Depending on barrel length and bore tightness, anything over 24.5 grains of powder may not be burnt or burnt efficiently. Four 20Ps and I have never gone over 24.3 of N133 in any of them with any weight or brand of bullet.

With that information then... (thank you hogpatrol...) I'm feeling like my newly acquired .20 cal collet for pull-down duty might have a job opportunity sooner than later.

I have a 26", 1:10 twist.

I currently have 10 rounds at & under... and another 40 rounds over your posted 24.3 max.... loaded with 32gr pills.

Im definately not in the mood for waste these days. I'm not opposed to pulling em down either. In hindsight, considering I have W748, H335 & CFE223 (and 2#s of N120)... Im likely just pulling all the 32gr loads & going back with a different powder over the BR4.

I bought that N120 as a "comparable" to any of the 4198s I just couldn't find... with the intention of stretching my N133 on hand for use with the 40's... but just cant bring myself to get past the N120s really shallow case fill enough to use it.

Thanks again all who contributed.

RP

 

[TheCZKid]

With 32 Vmax and N133 my 1:10 twist 24" WOA barrel does well with 24.0 grains. I have tired up to 25.5 with pretty good groups, as you see below. The 2nd column is grains, next is SD. Next is speed - last columns are group sizes per load. I actually went up to 26.3 and was seeing notable pressure signs, but up to 25.5 I think you'd be okay.

N133	23.9	19.5		3913					0.95
	24.0			3850		AR-M	1.850	1.848 to 1.850 good	0.25	0.35	0.49	0.40	0.84	0.74	0.75	0.56	0.77	0.61
	24.1	5.6		3913				224 Bushing 0 Shot	0.95
	24.2	8.7		3932					0.32	1.02
	24.3	42.0		3985					0.64
	24.7							AccurateShooter.com	0.64
	25.2			4034					0.56
	25.5			4070				25.7 .55"	0.40	0.39	0.88	1.01	0.55	0.51	1.88

Mine likes 8208 25.0 grains with 40 Vmax best so far.

 

[hogpatrol]

FWIW, My Quickload data for the 20P, 27" barrel, 35 Berger, 23 gr. of N133 shows 98.99% of propellant burnt.

 

[liasis33]

CZ, I have been unable to find 8208 and/or any of the 4198 powders, and its not for lack of effort. Had I found more N133, I'd be comparing my notes to yours, as that's pretty much what I loaded. Thanks for that data.

I am however going to pull down my current 32 gr loads & return their N133 back to the original plan of pushing the 40s... if for no other good reason that I dont have enuf N133 on hand to develop and produce both loads in PD plinkin quantities.

SBS provided some attractive QL data with the N120 at 22gr that yielded just under 55k psi & a 3900 ish velocity. That data is attractive to me. OTOH, I've all but a abandoned the N120 due to my projected starting charge weight of 19gr appearing to have such a poor looking load density / case fill. (See pic, earlier post) Whether for sake of safety or just mobile powder / poor column... IMO that case fill looks less than ideal...

And then again-again, Itd be nice to finish this thread with some quantified N120 data. Despite my visual judgement of a light-load looking, shallow case fill, Viht suggests a 19gr starting charge weight in .223 pushing a 40gr. And Hornady published a 19.5 gr starting charge weight of N120 in .223 also pushing a 40gr vmax. So...

To test the N120 or not to test the N120...

I've been back & forth on this so much I'm about to just build a 221 FB or 20VT to resolve the indecision.

 

[TheCZKid]

CZ, I have been unable to find 8208 and/or any of the 4198 powders, and its not for lack of effort. Had I found more N133, I'd be comparing my notes to yours, as that's pretty much what I loaded. Thanks for that data.

I am however going to pull down my current 32 gr loads & return their N133 back to the original plan of pushing the 40s... if for no other good reason that I dont have enuf N133 on hand to develop and produce both loads in PD plinkin quantities.

Yesterday I tested seating depth for 32 Vmax and 40 Vmax with my best loads using N133 for both. The 32 loads definitely have better groups, I was surprised how much better. So, if it were me, I'd go for finalizing a 32 Vmax load with the N133, but that was just my experience in my barrel, YMMV