• This Forum is for adults 18 years of age or over. By continuing to use this Forum you are confirming that you are 18 or older. No content shall be viewed by any person under 18 in California.

20-250 data

I was using 8208, 3/4 case full... didn’t get the speeds y’all was getting.. and pressure showed real quick in the warmer weather..
Now I’m at the neck/ shoulder junction (BRAI)w/ RL15, and everything is good
 
Gabe22BR said:
I was using 8208, 3/4 case full... didn’t get the speeds y’all was getting.. and pressure showed real quick in the warmer weather..
Now I’m at the neck/ shoulder junction (BRAI)w/ RL15, and everything is good
Click to expand...
RL15 is so accurate in my 20BRAI, I guess I just cant leave well enough alone.
 
Scooby-93 said:
Anyone had any fluctuations in pressure with there 20’s? Loaded up to 38.5gr of n550 with no pressure but at 38.5 the primer was flattening then 39gr the bolt was heavy. 39gr resulted in 4350fps with 39sbk.

I then done a OCW test from 37.2-38gr

I hit pressure at 37.4gr?

I done another OCW 36.2-37gr.

Accuracy node was 36.6 so went with that.

2 out of 6 rounds at 36.6 have had pressure signs in the form of a sticky bolt.

I can’t put my finger on why initially 38.5gr was the start of pressure and then all of a sudden I am getting intimating pressure at 36.6?

same batch brass, primers, bullets and powder. Temp has been the same give or take a few degrees.

there is no a total of 75 rounds down the tube with the break in procedure of x10 1 shot clean x3 3 shot clean x2 5 shot clean.

butchers bore shine is what I have used to clean, I have pulled a lot of carbon out the barrel but it’s took a lot of patches and brushing.

barrel is a bartlin 10twist
Click to expand...


Seems to me the 20-250 will spike quite quickly when compared to the 22-250. I’ve not loaded N550 in mine but the 20s hit the max pretty fast.

And considering a guy is extrapolating data feom some other source for this round o think it’s a good idea to start quite low and work up to where you want to be.
 
xswanted said:
Seems to me the 20-250 will spike quite quickly when compared to the 22-250. I’ve not loaded N550 in mine but the 20s hit the max pretty fast.

And considering a guy is extrapolating data feom some other source for this round o think it’s a good idea to start quite low and work up to where you want to be.
Click to expand...

i have 2 friends who shoot this calibre aswell, 1 shoots 40gr vmax with 38gr of n550 for 4250fps no issues of fluctuating pressure.
1 shoots the 55gr Berger with 37gr or of h4350 for 3700fps - again no pressure issues.

what I can not get my head around is why would I reach pressure initially at 38.5/39 and then for some reason find it 2-2.5 gr lower down

velocity needs to be around 4200 minimum, I built this rifle and went with this calibre for that reason, I might aswell of built a 204 or 20BR if I’m stuck around the 4000fps
 
Scooby-93 said:
i have 2 friends who shoot this calibre aswell, 1 shoots 40gr vmax with 38gr of n550 for 4250fps no issues of fluctuating pressure.
1 shoots the 55gr Berger with 37gr or of h4350 for 3700fps - again no pressure issues.

what I can not get my head around is why would I reach pressure initially at 38.5/39 and then for some reason find it 2-2.5 gr lower down

velocity needs to be around 4200 minimum, I built this rifle and went with this calibre for that reason, I might aswell of built a 204 or 20BR if I’m stuck around the 4000fps
Click to expand...


Same lot of powder?

Did you leave the powder in your measure for a day or two prior to the second test?

Did you clean the rifle before the second test?


Same seating depth?

Same outside temp?

Just trying to throw some things out there if you haven’t thought of them.
 
xswanted said:
Same lot of powder?

Did you leave the powder in your measure for a day or two prior to the second test?

Did you clean the rifle before the second test?


Same seating depth?

Same outside temp?

Just trying to throw some things out there if you haven’t thought of them.
Click to expand...
Hi yes same Lott of powder, bullets primers brass etc

same seating depth

same outside temp

yes I cleaned before each OCW test but fouled the barrel before I started the test.

could it be purely down to virgin cases?

To note...

I use a Forster bump shoulder/neck die and no matter how far I knocked the shoulders back the fired cases were showing resistance to chamber and extract, it wasn’t untill I put them
Through a FL die with the guts removed that I was then able to chamber and extract the case with ease.

i think the body of the case has expanded and possibly given me false pressure signs on extraction and that is also why I struggled to chamber and extract fired cases unless they went through the FL die.

Am I missing something here?

thanks for any Input
 
I doubt this is it, but low pressure can be almost as dangerous as high pressure and give a lot of the same signs.

2020 and a lot of us still use what we believe to be high pressure signs from the 40’s and 50’s. Most of what shows up more times than not is way past peak pressures.

Not knocking anyone as I am guilty of it as well.
 
You must log in or register to reply here.

Upgrades & Donations

This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.


Click Upgrade Membership Button ABOVE to get Gold or Silver Status.

You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.


To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.

Classified Ads

Forum statistics

Threads
164,903
Messages
2,186,320
Members
78,579
Latest member
Gunman300

Share This Page

Back
Top