20 practical project done, but

[Doug30racer]

I am starting to shot it a little, and its not bad. It shots ok, but nothing with the "wow" factor yet. Beening the rifle is 15 pounds and seems very balanced, I do have higher expectations for it. So I am wonder ( on a the average) what kind of oal (with 40gr) you guys have. I am 2.185 to 2.190 to stay way from the lands. Which is not a big deal, but this is the but.... I see post on here about speeds of 3800fps to up around 3950 posted with not problems. I have used blc-2 and aa2230 powders so far. if i get near a 3700fps i have pressure issues. the blc-s is worse than the aa2230. I am going to get some benchmark and 8208 to try next. I am wondering if the fact that i have to be so short in the chamber is hurting the speed and causing the pressure signs?. Or are people that full of bs that 3650fps is more the reality of the 20 practical. And before the pissy responses come in, i do understand the amount of factors the are combined is the equation. So what are you guys using and what oal fits for you?

ps. i tried to add a picture of the rifle, but no idea how. lol

 

[Doug30racer]

 

[pacificman]

Very nice looking rifle there! I own two 20 practicals one with pac-nor barrel and one with criterion barrel.
pac-nor is 28 inch with 3 groove rifling the criterion is 26 inch with 6 groove rifling.
I get 3860 fps. with the pac-nor and 3650 with the criterion barrel....both very accurate.
I'm thinking that with the 3 groove rifling and 2 more inches in length allows for a bit more speed
in the pac-nor barrel. It would be nice to get more speed with the criterion barrel but I start to see
pressure signs when pushed near 3700 fps. With the accuracy at "only" 3650 fps. I am very pleased
with the velocity. Accuracy over speed is always preferable to me. I'm also using RL-10x powder in
both rifles. 24.0 grains in the pac-nor and 22.5 in the criterion. also when I used h4198 in the pac-nor
I used 21.0 grains with very good accuracy but velocity was only 3550 fps. I'm sure there is a powder
bullet combo that would allow more speed in your rifle but if it were me I would settle on a accurate
load and call it good. I would also assume that my pac-nor barrel will not last as long as the criterion because
I'm pushing them near max. With the criterion barrel I just aim a bit higher in the rat fields.....LOL I'm using 40grain v-max in both rifles with about 10 thou jump to the lands.... also both barrels are 1 in 11 twist.

 

[pdhntr]

My 20 P is a 24" Krieger on an AR platform. Did a lot of testing with different powder through two different chronographs, one in front of the other.

I tested and am using 35 gr. Bergers. The best accuracy and speed was with Benchmark. 26.0 gr. gave 3757 fps. average, and it was what I considered a "warm" load. I have since backed down to 25.5 as I get the same accuracy and I don't want to shoot this barrel out as it is way more accurate than I expected.

What bullet are you using?

Jim

 

[Wirelessguy2005]

To be honest I don't think speeds of 3,900 is realistic with a 40 grain bullet in the 20 practical case. There are guys that get that kinda speed with the 20 practical but they are leaning hard on the case which causes a need for frequent trimming and full length sizing due to brass growth. You will probably see a little better speed and less pressure with 8208 and or accurate 2520.
If you are interested in getting more speed and better efficiency from your 20 you might want to take a look at the 20SCC or 20-223ai. Both of these cartridges utilize an ackley improved should and in my experience will provide better efficiency, speed, and wow factor when the bullet connects with the target.

 

[Doug30racer]

My 20 P is a 24" Krieger on an AR platform. Did a lot of testing with different powder through two different chronographs, one in front of the other.

I tested and am using 35 gr. Bergers. The best accuracy and speed was with Benchmark. 26.0 gr. gave 3757 fps. average, and it was what I considered a "warm" load. I have since backed down to 25.5 as I get the same accuracy and I don't want to shoot this barrel out as it is way more accurate than I expected.

What bullet are you using?

Jim

Built it to shoot 40some. But which one is under investigation

 

[LitLBoy]

You will be really happy when you try some 8208 and Sierra 39BK's
LitLBoy

 

[Tesoro]

I have a 24in pacnor 3 groove WOA on my AR that I am playing with. I didnt really have any loads to work off with my setup but just some recommended powder choices. I have a big box of 39sbk so been using them. So far have shot best 3x .153 and .169 and plenty 5x in the .2-3 range so I am happy. I read many reports of 3800 to 3900 velocities with 39sbk in bolts. I tried it and I went to reported 26.6g of benchmark was blowing primers like popcorn and leaving some pretty impressive ejector engravings and one more firing away from head separation! With that load i peaked at 4010. Obviously this is way over the top so I am working now in the mid 25g range. If I stick at 3825 with 25.7 then no ejector marks and still some round left on the primer edges but the recoil feels a bit hot and my brass grows about 2 tho. I am not experienced in this but have tried to educate myself. I think like alot of new 'wildcatters' we get fixed on matching reported velocities and its even worse when I shot my best 3x group at 4000 fps! I keep having to go back to ballistic tables to compare 200 fps effect at 400 yds and it 'aint no big deal'..
I also tried n133 on a recommendation but found it to create equal pressure signs but more blast with about 100fps less velocities. The benchmark seems to be a popular powder for 20p but I would like to try one more and reading here 8208 & 2520 might help reduce pressure signs. It seems to me and have read elsewhere that the 20p is considered to be a rather hot cartridge when shooting it at velocities equal to or surpassing the 204. To me the sweet part of the 20p is no fireforming and can shoot accurately with 5c LC brass. Once I get this down I dont see shooting my 223 upper much more. The 39-40gr 20 cal bullet makes much more sense to me downrange.

Interestingly the last time I was shooting some test loads I shot about 15 of them before I realized I had forgotten to put in my earplugs. That wouldnt happen with my 223!


If any of you have to offer any load ranges to start at with 8208 or 2520 I would appreciate that. And any other tips. thx

 

[moorepower]

I have a 24in pacnor 3 groove WOA on my AR that I am playing with. I didnt really have any loads to work off with my setup but just some recommended powder choices. I have a big box of 39sbk so been using them. So far have shot best 3x .153 and .169 and plenty 5x in the .2-3 range so I am happy. I read many reports of 3800 to 3900 velocities with 39sbk in bolts. I tried it and I went to reported 26.0g of benchmark was blowing primers like popcorn and leaving some pretty impressive ejector engravings and one more firing away from head separation! With that load i peaked at 4010. Obviously this is way over the top so I am working now in the mid 25g range. If I stick at 3825 with 25.7 then no ejector marks and still some round left on the primer edges but the recoil feels a bit hot and my brass grows about 2 tho. I am not experienced in this but have tried to educate myself. I think like alot of new 'wildcatters' we get fixed on matching reported velocities and its even worse when I shot my best 3x group at 4000 fps! I keep having to go back to ballistic tables to compare 200 fps effect at 400 yds and it 'aint no big deal'..
I also tried n133 on a recommendation but found it to create equal pressure signs but more blast with about 100fps less velocities. The benchmark seems to be a popular powder for 20p but I would like to try one more and reading here 8208 & 2520 might help reduce pressure signs. It seems to me and have read elsewhere that the 20p is considered to be a rather hot cartridge when shooting it at velocities equal to or surpassing the 204. To me the sweet part of the 20p is no fireforming and can shoot accurately with 5c LC brass. Once I get this down I dont see shooting my 223 upper much more. The 39-40gr 20 cal bullet makes much more sense to me downrange.

Interestingly the last time I was shooting some test loads I shot about 15 of them before I realized I had forgotten to put in my earplugs. That wouldnt happen with my 223!


If any of you have to offer any load ranges to start at with 8208 or 2520 I would appreciate that. And any other tips. thx

Western powder has load data with psi for the Tac 20. The highest velocity they get with a 40 grain bullet is 3708 with TAC and 3835 with 2520, both within a few fps of 63kpsi. They got 3697 with 2230/ Xterminator. I don't own a Tac 20 but supposedly they are about .2 grains higher capacity. That tells me that some of the loads I see that are "safe in my gun" and show 'no psi signs" perhaps are in the 65-70 kpsi range.

 

[Tesoro]

Western powder has load data with psi for the Tac 20. The highest velocity they get with a 40 grain bullet is 3708 with TAC and 3835 with 2520, both within a few fps of 63kpsi. They got 3697 with 2230/ Xterminator. I don't own a Tac 20 but supposedly they are about .2 grains higher capacity. That tells me that some of the loads I see that are "safe in my gun" and show 'no psi signs" perhaps are in the 65-70 kpsi range.

Thanks!

 

[Doug30racer]

i am going to put some together with benchmark and 8208 in the next few days hopefully. If i can find something in the 3800 range and sub 1/2 groups at 100, i will be happy.

I was wondering what over all length you guys are seeing?

 

[Tesoro]

You should easily obtain that goalif your rifle is okay. Yesterday I did another test round at 25.5g benchmark with diff primers(br4) and I got right at 3800 with 39sbk and much rounder primers. Thats on my gun not yours.

What do mean what oal are you all seeing?

 

[GrocMax]

40 vmax has liked .005"-.015" jump in every zero freebore 20P I've ever seen. This works out to approx. 2.220" (+/- a few) OAL.
25.0g-25.2g Benchmark = 3750FPS, case volume dependent, and long case life.

The other powder I've used a lot of is WC844, my batch is just a tick slower than H335. 26.0g or so.

Be careful of seating force, too small of neck sizing= crushed ogives. Depending on brass a +.002" fit (before/after bullet seating neck diameter) may be too much.

 

[germanlongbow]

N133 works great in mine.

 

[ratbuster]

With 2 different 20 Practical 26" Criterion barrels I get at or around 3850 fps (40 gn Vmax) with good brass life and best accuracy with H4198, Benchmark and H335. 3900 fps is pushing it and will prob shorten brass life. One day when testing the limits with 32 grain Z max I actually got 4443 fps (3 shot average) which is way over pressure.

I built two AR's with 24" X Caliber barrels, one a 20 Practical and a 204 Ruger. Both of those rifles had velocities that were 250 fps slower than expected.

 

[Tesoro]

Ok I am done...the rock chucks are out and load experimenting takes alot of time. Time to load up and head to eastern oregon! I settled on 25.5g benchmark in my setup. One hole accuracy at 100yds if I do my thing on the other end. I switched from Rem 71/2bench to BR-4 and much much better. The rems were a bit smaller in diameter and seated lightly. I think this was causing my primers to look worse than they should have been. The br-4's are tad larger in diameter like 001 to 0015 and could definitely feel a tighter grab when hand priming. The br-4's at 25.5g look like good factory load primers after being shot. Interesting what just a thou more in diameter does. Interestingly the rem and br-4 have same cup thickness. 3800fps with 39sbk is fine with me! and esp if I can get better case life.

Next winter I will play around with n133 again and other recommendations given in this thread. thx.

 

[Doug30racer]

I too found 25. 4 grains of benchmark gives me one hole accuracy and 3800 fps. Very happy with that and pressure is plenty high as well. But my chamber is a hair short so my over all length is also shorter causing the extra bit of pressure. Going to try a bit of 8208 just to hear it gout bang

 

[Tesoro]

I too found 25. 4 grains of benchmark gives me one hole accuracy and 3800 fps. Very happy with that and pressure is plenty high as well. But my chamber is a hair short so my over all length is also shorter causing the extra bit of pressure. Going to try a bit of 8208 just to hear it gout bang

What barrel you shooting that with?

 

[Doug30racer]

What barrel you shooting that with?

Bartlien 1-11 twist. 26in long

 

[GrocMax]

3800FPS with 39g-40g 25.4g BM 26" and 94g-95g weight (guessing Lapua) brass is totally believable to me. 8208 is generally just a little slower than BM in similar circumstances. Use what works for you, wide variety of powders that will work for us.