Thank you to the 20 Practical Gurus and some rookie questions

[MikeT49]

Probably not the correct way to do things, however, I have removed my original inquiry as it was obviously not to the point and has led to this thread heading down some spur lines. My questions on barrel seasoning and small case pressure signs have been answered. Thanks to all who have provided info. This thread might prove useful to those looking to do a 20P. There is useful info on load data & component suggestions. There is also some discussion of the variants, 20C, 20I, 20PBR, etc.

 

[MrMajestic]

Welcome aboard and say goodbye to your bank account as these guys will deplete it!
I wouldn't worry about the numbers and let your targets be the judge. I joke with a guy at the range that I would duct tape a cleaning rod to gun to help with extraction if the groups were small enough. Slower is easier as all it takes is a turn of the knob..

 

[MikeT49]

I know I shouldn't get too OCD on numbers, but I am recently retired nuc eng tech. Sweating details is kinda inherent. I need to rephrase my question on case capacity now that I rechecked and the difference is only about 1%. So how much of a percentage change in case capacity does it take to cause a measurable change in MV? In the meantime I will enjoy shooting the 20P till it settles down and then perhaps get OCD on numbers.

 

[hogpatrol]

My 2¢ Overthinking this cartridge seems to enjoy a rather large audience. Keep the 20 Practical practical. Use one type of brass. Work up a load that is accurate and use MV numbers only for a drop chart.

 

[MrMajestic]

Unfortunately my "new" friend your acute attention to detail will cause you loss of sleep/ulcers/stress in this game. Lot #'s, burn rates, and metallurgical idiosyncrasies make this a mathematical nightmare. Luke, my son, let the target be your guide...it's really all that matters.

 

[GrocMax]

Sounds like you're on the right track. In my opinion, 3850 with a 26" and 39-40's is pushing the brass pretty hard. Get a small rifle primer pocket go/No-go gauge and watch the stretch. Back it down to 3700-3750 or so and see if you can find the lower node. Neither the target or critter will care its slower, but the brass will.

BTW if you think about the small case capacity difference with the same powder charge as a Pressure-Volume curve like an internal combustion engine it will make sense, think Expansion Ratio or Compression Ratio of the entire barrel/chamber system.

 

[MikeT49]

I hear ya. I used to use a KISS method. Get the load dialed and then use the chrony for come ups. Unfortunately, I have acquired a Labradar and suddenly I have a need to complicate things and find ways to play with the unit. I know I'm leaning on it a smidge and after the PITA of forming a large bunch of brass, I have considered backing off. But, I still have a need for speed that I developed in my younger days. I hope to be cured someday. And maybe not.

 

[MrMajestic]

I have some extra duct tape...

 

[GrocMax]

20P is a good candidate for pushing the limits of the brass because its cheap and you don't need a bunch of forming steps, I throw away a case at the most minor imperfection, whereas 6BR Lap brass I can't part with it unless its fubar.

But if the primer pocket opens up in one firing, BACK OFF. My opinion a reasonable life for 223 brass to be pushed hard is 4-5 reloads. Different powders will stretch the pockets differently, I guess it depends on the pressure curve, AA2200 is a good example, it acts like it has a wide 'peak' on pressure curve rather than a sharp one. It shouldn't be able to give better velocity but it does.

That X-cal 3 groove is already way past broke in at 182 rds from my experience, have had several.

 

[MikeT49]

Unfortunately my "new" friend your acute attention to detail will cause you loss of sleep/ulcers/stress in this game. Lot #'s, burn rates, and metallurgical idiosyncrasies make this a mathematical nightmare. Luke, my son, let the target be your guide...it's really all that matters.

Believe me I will not get too spun up about this or anything for that matter. I perhaps need to learn how to phrase my questions better. I don't have one of them wifey things, so that right there makes things very peaceful. (Hopefully, that wasn't politically incorrect, don't care.) Here are my don'ts: don't do bullet sorting by whatever method, don't care; I don't sort brass unless it's as bad the last batch of WW 22-250 brass I procured, after that I quit buying WW brass; no neck turning; no bullet runout stuff. Perhaps because I'm too lazy or because for what I do it's a waste of time; don't uniform primer pockets. I do debur the primer flashhole; I did switch from neck sizing to shoulder bump; cases are trimmed to uniform length; I do pay attention to primer seating and I weigh every charge with a Chargemaster, double check with beam scale once in a while. I screw budget custom barrels on budget Marlin X gun receivers and normally put them in Boyd's stocks, seeing as how there are no other aftermarket stocks available that I know of. Budget glass w Burris Sig Z-rings. I assemble them for me for hunting. Triggers are excellant, easy to work on, easy to get to a no creep stage & clean break. IMO better than the Savage's I've tried. Good thing as there are no aftermarket replacements available. I don't really like the blade in the trigger (it adds 8 to 11oz), but if you treat it as two stage you can almost get used to it. Don't do competitions. My goal is 1/2 MOA 3 shot groups (repeatable) for medium game size cartridges, 5 shot groups for the varmint stuff. Usually I can get there. With the 20 Practical it was almost effortless. I think sometimes that maybe the holy grail of a one hole group (5 shots, not one) perhaps is attainable with it. But that would involve getting nutzoid anal and start using more time consuming methods to get there....Nah, not gonna happen.

I have some extra duct tape...

It took me a second.....pause & clean adult beverage spray off tablet screen. This is a prime example of why I decided to join your forum. World class knowledge and as a bonus world class clowns. It doesn't get much better.

 

[MikeT49]

20P is a good candidate for pushing the limits of the brass because its cheap and you don't need a bunch of forming steps, I throw away a case at the most minor imperfection, whereas 6BR Lap brass I can't part with it unless its fubar.

But if the primer pocket opens up in one firing, BACK OFF. My opinion a reasonable life for 223 brass to be pushed hard is 4-5 reloads. Different powders will stretch the pockets differently, I guess it depends on the pressure curve, AA2200 is a good example, it acts like it has a wide 'peak' on pressure curve rather than a sharp one. It shouldn't be able to give better velocity but it does.

That X-cal 3 groove is already way past broke in at 182 rds from my experience, have had several.

Thanks for the info. I was hoping someone with one of these barrels would chime in. I will quit putzing around and do the final tweaks on my load. First ever prairie dog hunt coming up soon, SE Montana.
This did remind me that I need to get educated on pressure signs for these dinker cartridges. For example when I first got the 20P, I tried H335. Kept going up in charge, looking for pressure signs, got to 37gr, yikes! Speed was 4256fps on the Magnetospeed. Slightly stiff bolt lift. It took normal pressure to remove the primer, I expected it to fall out. Slight cratering in the firing pin dimple and if you looked really hard with a magnifying lamp, you could barely see an ejector mark. I had to be seriously over pressure. Why did it not show more? Won't do that again!

 

[GrocMax]

This might sound crazy to some, but a decent way to guesstimate going above say ~50Kpsi in a 223 case based round and a std Savage ~.060" OD firing pin is to do load dev with a CCI400 primer. When it starts to look like its going to blank/pierce, switch to your preferred thick cup unit and work up carefully.

 

[GrocMax]

Oh, and what has been a go-to load for many is about 25g of Benchmark, 7 1/2 or 450 or BR4 primer, and a 40 vmax about .015" off the lands to start. 39BK will be similar.

Mine is LC brass, 25g BM a 7 1/2 and a 40vmax .015" off. 3750 in a long tube. I'd guess this is real close to a max book load if it was SAAMI approved 57kpsi mean. Others report similar results. Try it. 8208XBR is very very close to BM in this round on a grain for grain basis at that charge weight range, but may or may not show the same accuracy for you.

 

[AlNyhus]

Mike T49: My advice is to use Lapua cases exclusively. Quality cases are an investment that will let you concentrate on other areas of the package.

Good shootin'. -Al

 

[hogpatrol]

Mike T49: My advice is to use Lapua cases exclusively. Quality cases are an investment that will let you concentrate on other areas of the package.

Good shootin'. -Al

Al, all well and good but then he wouldn't be shooting a 20 Practical. It'd be a 20PBR.

 

[MikeT49]

Al, all well and good but then he wouldn't be shooting a 20 Practical. It'd be a 20PBR.

You gotta remember I'm just at the grasshopper stage, past nub grasshopper and maybe to green belt.
My guess is it's a poke at the Bench Rest crowd? Actually, being originally from WI, the first thing I thought of was Pabst Blue Ribbon, they do cases but don't do cartridges that I know of. Or Practical Beyond Resources? The only barrels I have screwed on so far are also "Practicals" 243 Practical, 257 Practical and a 277 Practical. Although, technically, the 277 sorta doesn't count on account of the longer neck.

 

[MikeT49]

This might sound crazy to some, but a decent way to guesstimate going above say ~50Kpsi in a 223 case based round and a std Savage ~.060" OD firing pin is to do load dev with a CCI400 primer. When it starts to look like its going to blank/pierce, switch to your preferred thick cup unit and work up carefully.

That sounds like a possible way to get the the cartridge to talk to you. Like: its saying "back off dummy you're getting stupid" I will test that someday, thanks

 

[MikeT49]

Mike T49: My advice is to use Lapua cases exclusively. Quality cases are an investment that will let you concentrate on other areas of the package.

Good shootin'. -Al

I have less than a stellar opinion of Lapua brass. Please remember, it's just an opinion and "opinions are like a$$holes, everybodys got one and most of 'em stink" I have purchased one box of 22-250 Lapua brass. I know, not much of a sample. The dweeb or dweebete that did the final annealing must not have been paying attention. I had been using range pick-up WW brass and some WW cases a friend gave me. Obama was still in and the panic was still on, it was all I could get. Got a nice shooting load developed. 55BK and 36.1 gr of 4064 BR4s. Then Midway got some Lapua and it was on sale with free shipping. Real purty stuff. I did my own QC inspection and it was spot on. The Lapua case capacity (measured) was slightly more than the WW. So I drink the Koolade and did not do any case prep. I load some 4064 charges in the Lapua brass from 34.8 to 36.3 with 55BKs and BR2s. Shoot first round, no problem. Second round I get the "bolt click" thing right at the top, read about it never felt it before. Third round, same thing. Fourth round, extremely heavy bolt lift. Should have stopped. Fifth round I had to whack the bolt open. Sixth round I don't shoot. Primer on the last round I shot was slightly flat, no cratering; no ejector marks. In order for me to get this batch of brass to shoot without the pressure signs I had to full length size the cases 3 times. Now it will shoot. I spit out the Koolade. Not worth the $. I will see if it shoots better than any other brass per the hype. I have 156 new prepped WW cases ready if my results stink.

 

[AlNyhus]

Your starting load with the Lapua cases was a full .8 gr. above what IMR shows as a starting load for the 55's.

For what it's worth.....

 

[MikeT49]

Your starting load with the Lapua cases was a full .8 gr. above what IMR shows as a starting load for the 55's.

For what it's worth.....

You are correct sir. And..... 2.2 above Sierra, 2.8 above Lyman and 3.3 above Berger.