Speer 39gr TNT .20P

[Fast14riot]

I've got a couple hundred Speer 39gr TNT I picked up cheap I wanted to try out in my .20P AR. Barrel is 10 twist, 3 groove poly rifling 24" spr profile.

I last minute decided to shoot a "walking varmint" match this coming weekend and had a thought of shooting my .20 instead of my 6mmRem. But, I'm out of imr4198 and 32vmax bullets.

I do have H335, BL-C(2), 8208 and 2230C. I'm thinking the H335 or 8208 would be my best bet, but I don't have any data on those for reasonable accuracy in my barrel.

Anyone have any good loads with the 39/40gr bullets and these powders? I was thinking of just dropping 26gr H335 and hope it holds 1moa. This steel match is 100 to 225 yards so I don't need really, really accurate or fast ammo, but it helps.

Bonus, I work late all this week and can't get to the range before the match.

Also, does anyone have the BTO for the 39gr TNT?

TIA

-Alexander

 

[L.Sherm]

Don't rule out the 2230 shoots very well in my 20 prac with 34 v-nitemares

 

[Fast14riot]

I do not have regular 2230, I have 2230C, which I use 2460 data for.

 

[JLT]

Out to 225 . . . just pick a load. Out of a decent SPR profile .20P barrel, you could seat the bullets backwards and still get MOA.

I'm assuming you're limited to mag length. I seat the TNTs at 2.260" cartridge OAL and they feed fine. The TNT has a fairly long nose, so seating out to anywhere close to the lands is not an option in an AR platform.

 

[ab_bentley]

Out to 225 . . . just pick a load. Out of a decent SPR profile .20P barrel, you could seat the bullets backwards and still MOA

Just about the truth right there.

 

[Ledd Slinger]

All of the powders you listed as on hand will work with the 20 Prac. But nobody can tell you anything about how accurate YOUR rifle is going to be with a load, while YOU are shooting it. Just gotta get out and test it for yourself. The paper will let you know

 

[Fast14riot]

All of the powders you listed as on hand will work with the 20 Prac. But nobody can tell you anything about how accurate YOUR rifle is going to be with a load, while YOU are shooting it. Just gotta get out and test it for yourself. The paper will let you know

Yes, I know I will need to tune it, I was just curious if there was a known good node for any of those listed.

I ended up using 26.5 BL-C(2) and seating them at 2.250. Should net me between 3500-3600fps.

 

[Ledd Slinger]

Yes, I know I will need to tune it, I was just curious if there was a known good node for any of those listed.

I ended up using 26.5 BL-C(2) and seating them at 2.250. Should net me between 3500-3600fps.

A "node" will also vary from rifle to rifle, barrel to barrel. A charge weight in the middle of a node for one rifle won't necessarily be the same for any other rifle.

BLC-2 would be a good powder. I always have good luck with that powder in my 204R and a couple other cartridges.

I've recently been having really good luck with 8208 since I started testing it in a couple AR rifles. I now use it in my 6.8 SPC and just found a good load with it in my 20 TAC AR-15. Below is a pic of a 5 shot group at 100 yards with 8208 and 34gr bullets in my 20 TAC. For 39gr in a 20 Prac, I would recommend starting a full grain or more less than the charge listed in my target picture. Pay no attention to the speed listed on the picture. I think my Chronograph was acting up and that speed is greatly exaggerated because .2gr more of 8208 (25.9 gr) later read speeds of 3660 fps.

 

[Fast14riot]

Thanks for the info, yes every barrel is different, but some loads just work well across many rifles too.

I took a middle of the road load from 20Tac data and I shouldn't be too far off.

I haven't tried 8208 in my 6.8 yet, but I have a 24" barrel and use H335 now.

 

[Ledd Slinger]

Thanks for the info, yes every barrel is different, but some loads just work well across many rifles too.

I took a middle of the road load from 20Tac data and I shouldn't be too far off.

I haven't tried 8208 in my 6.8 yet, but I have a 24" barrel and use H335 now.

My 6.8 is a 20" barrel. Never chronographed the load because I know it's not a fast cartridge, but it will shoot 5 shots with Hornady 110gr HP bullets a little less than 3/4" at 100 yards. Not overly accurate, but was the most accurate of the loads I tested and I never expected that caliber to be to be a tack driver either so I'm happy with it. Can't recall the charge weight of 8208 I use in it. Would have to dig into my records.

 

[GrocMax]

For H335 start around 25g, I end up at 26g for uncoated and a little more than that for coated, 3700+ in full length (24" +) barrels. Most of our 20 Prac zero freebore barrels love .010"-.020" jump.

 

[ab_bentley]

Benchmark @ 23gr and work up. I ended up @ 25.2gr with 3855 and a 40gr vmax. Accuracy has been unter half MOA to 600yds.

Adam

 

[GrocMax]

ab_bentley -

How's brass life with that load? Had a chance to get many firings yet?

 

[ab_bentley]

ab_bentley -

How's brass life with that load? Had a chance to get many firings yet?

I have close to 750rds through this rifle, so 7+ firings on my brass. Aside from a few split necks from poor brass quality, it seems it'll last quite a while.

Adam

 

[Fast14riot]

Some nice groups, I'll spend more time building a load later, I may even switch to Berger. I bought these bullets because they were cheap and I have liked the tnt in other flavors too. Having a 10 twist poly rifled barrel I'm going to want to use the heavier pills because I can.

 

[JLT]

Some nice groups, I'll spend more time building a load later, I may even switch to Berger. I bought these bullets because they were cheap and I have liked the tnt in other flavors too. Having a 10 twist poly rifled barrel I'm going to want to use the heavier pills because I can.

Try the 39 gr. Sierra BKs. You won't be disappointed!

 

[Fast14riot]

Just got home from the match, the 26.5gr of BL-C(2) under the 39 TNT proved to be good enough for 3rd place. Was one of the toughest matches I have ever shot. Standing 5 shots 3.5 minutes, 5 silhouette targets in random order and distance called by your spotter 1 minute break, 5 more shots in another 3.5 minutes again in a different random order! Two strings of 10 rounds standing, then two rounds of 10 sitting or kneeling. No shooting jackets, no hipower slings, strictly what you would carry afield for varmint shooting. Had steady 15-18 knot wind with 24-26+ knot gusts too. Needless to say, high score for the match was 21/40, I shot 17/40.

I'll be starting with this load on paper soon, it worked pretty darn good in some real tough conditions!

-Alexander