20-222 Pressure Test Data

[Esoteric Junkie]

Hello Everyone,
Below is the pressure test data that was recently completed in my 20-222. Specs: Borden Alpine action with very close firing pin fit, Pacnor 11 twist barrel. .230" neck. Win brass. We used RL-7 and N-201 powders and 32 & 40gr V-max bullets. The rifle opened easily and the same with all test loads. We only shot one round of each powder increment so there be slight pressure variations in this data, however it gives a very accurate measurement and guide to follow. Three to five round tests would give a better average. Please keep in mind that it is common to have 2000-4000 psi variations for the same load and less that 1000psi variation is very good.

Test equipment: Oehler 83 with Vishay Micro Measurement strain gages. All testing performed indoors. Approximate indoor temperature was 70 degrees.

Data Current 1/13/15 20-222 Pressure Data
Bullet 32gr V-Max
Powder Velocity Pressure PSI
18.5/RL 7 3438 39600
18.8/RL 7 3507 43400
19.1/RL 7 3537 44400
19.4/RL 7 3546 43500
19.7/RL 7 3609 45000
20.0/RL 7 3651 46500
20.3/RL 7 3675 49500
20.6/RL 7 3699 48100
20.9/RL 7 3751 50400
21.2/RL 7 3872 55600
21.5/RL 7 3920 58300
21.8/RL 7 3957 60600
22.1/RL 7 3972 62000
22.5/RL 7 4038 63200

Bullet 32gr V-max
Powder Velocity Pressure PSI
23.5/N201 3721 48500
23.8/N201 3671 46800
24.1/N201 3775 50800
24.4/N201 0000 53300 (No chronograph reading)
24.7/N201 3922 55100
25.0/N201 3887 53900
25.3/N201 4005 58400

Bullet 40gr V-max
Powder Velocity Pressure PSI
17.3/RL 7 3129 43000
18.5/RL 7 3249 44700
19.1/RL 7 3344 48500
19.7/RL 7 3507 59000
20.0/RL 7 3432 50600
20.3/RL 7 3601 60100

Bullet 40gr V-max
Powder Velocity Pressure PSI
21.5/N201 3361 47200
22.0/N201 3357 45900
22.5/N201 3446 49200
22.8/N201 3402 48200
23.0/N201 3497 53300
23.3/N201 3578 55900
23.5/N201 3628 57800
23.8/N201 3639 57600
24.0/N201 3657 59500
24.3/N201 3704 61300
24.5/N201 3773 63100
24.8/N201 3758 63900

It is clear from the pressure data that N-201 is a better powder than RL-7 for this combination.

Any questions let me know.

EJ

[csterner]

I know it's a wildcat and therefore no SAAMI Spec but what would be an approx max for this?

[Esoteric Junkie]

I like working in the 59-60K range. Good brass is necessary. Soft brass will not work properly at these pressure levels.

We had an issue this week in a 458 B&M and the only difference was Federal brass which was too soft and caused extraction issues (60K psi loads).

EJ

[csterner]

Makes good sense. Thanks for posting this. Very informative.

[Chuck Miller]

Thanks for posting the info, my load in my 2 rifles is 21.8grs of RL7 and a 32gr Vmax. Nice to see the numbers on it.

[dungheap]

Interesting!

Any idea why the pressure drops as the charges increase (sometimes) with the 32 grainers?

Have you done any testing with other powders at this point, or do you plan to down the road?

Going way back, I started with some Saubier data that was posted by NV Reloader using QuickLoad information, where there were at least a dozen powders listed, probably more. I'd LOVE to see what that would look like with this equipment.

[Bill K]

Originally Posted by Esoteric Junkie

I like working in the 59-60K range. Good brass is necessary. Soft brass will not work properly at these pressure levels.

We had an issue this week in a 458 B&M and the only difference was Federal brass which was too soft and caused extraction issues (60K psi loads).

EJ

Just be careful in those upper ranges, with your firearms. Things can come apart very fast and without notice. Bill K

[Esoteric Junkie]

BillK,
Rest assured we have the situation under control

Dungheap,
My plans for this Pacnor barrel are to keep the testing to a minimal level as this is going to be my go to prairie dog rifle this year. I do not want to shoot out the barrel testing loads and pressure. It shoots lights out now and there is no need in smoking the throat before dog season.

I would be happy to pressure test any bullet and powder combination as long as someone or a group of people were to donate a barrel and money for the chamber job. Barrels usually run $250-350 and a chamber job between $200-350 depending on who does the work. So a dedicated test barrel would cost between $450-$700. The strain gages that we use only cost about $25-30 each, however the Oehler 83 cost north of $10K. The strain gages are epoxied to the barrel and on for good once applied. I have several bolt face sizes and can test any caliber or bullet combination from 17 up. It would be interesting to get a .17 caliber barrel and chamber it for 17 Fireball/Mach IV and do pressure/velocity testing, then rechamber and test the same barrel in a .17 Remington. Food for thought.

EJ