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bri2506

.20 practical loads

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Has anyone any loads max min for 39 grn using v133. I've bought a rifle that came with a load but it has heavy bolt lift and is showing pressure signs on cases. Was looking to work up my own load but can't find any in any of the manuals. Any help would be grand cheers 

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23 grns - 24.5grns 

What's the load the rifle came with?  If it's n133 pull one and weigh the powder!!

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24.8. And I  weighed one to check. He had only been using a neck die and cases were stiff to load so I bumped 10 back and loaded them but still a heavy bolt lift and flattened primers. Been looking at bits on Internet and they are saying use 20 tac loading or ruger with 2 grains less. Just after advice 

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Just start at 23.0 grns and work up.

No doubt everyone will have a different method of prepping their cases, but if you get a FLS 223 die Redding type s bushing die with the right size bushing,and 20 cal expander,plus 223 seater die, that will be all you need just fls everytime so bolt just closes without being tight on case(don't just bump back 10 thou), check length too and trim as 223.

 

 

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I’ve had my Sako A1 .20Prac since 2013 and the load developed at the time ended up at 24grns of N133 (old’ish pot left over from .223 days) with cci400’s, I did a side by side test with Rem7.5’s but the cci’s came out with a narrower FPS spread. 

But there has always been a bit of cratering on the primers...nothing untoward and I put that down to the thickness of the 400’s cup.... a few months ago, I decided to go back to basics including measuring the chamber after chrono’ing that load and finding it short on FPS compared to the original pot of powder. 

At  the same time... I went for the CCI450 Magnum primers with their thicker cup having done a side by side with the BR4’s (didn’t bother with the Rem7.5’s).

On the basis that the Magnum primers are supposed to be hotter, I dropped back to 23.2 guns and came up in .2 grn increments but my groups didn’t start tightening until the speed got to 3600fps and the 39grn SBK’s went into their next published  Ballistic coefficient band at .287

I ended up with the best group at 24.6grns but dropped it back to 24.4grns to allow a bit for warmer weather. 

Dies-wise... I run all my cleaned/annealed cases through the chamber, and for those that are tight I now use a Forster bushing bump neck sizing die that will also bump the shoulder.

If they all chamber without a problem I might use a Redding Type S with a 17/20 spindle and a carbide button.  Followed by a Wilson to seat 12thou off the lands, I’ll try some at 10thou first on the next batch ready and waiting following a quick dip in the salt.

 

cheers

 

fizz

 

 

FF9CF1B1-4FC4-436C-9A47-5ED9A4CB921F.jpeg

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I tried putting the loads it came with over the  chrono yesterday and the bolt nearly locked up solid. So much so that just as I got the bolt open the spiral staircaseing handle snapped off. Not impressed is not the word. 

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Lawton 7000

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1 hour ago, bri2506 said:

I tried putting the loads it came with over the  chrono yesterday and the bolt nearly locked up solid. So much so that just as I got the bolt open the spiral staircaseing handle snapped off. Not impressed is not the word. 

So you knew you were getting a tight bolt lift, and  it was showing pressure signs on the cases,but still carried on wacking more through it !!!, Might of been a better idea to have pulled them all and start again.

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In hindsight you’re right. They were some loads that I had loaded of the original load but with 2 thou shoulder bump in cases. The load was developed by the gunsmith who built the rifle so you would have thought the load should have been some where near. I thought bumping the shoulder might have sorted the bolt lift issues. The bolt weld was not the best in first place by the looks of things. 

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5 hours ago, bri2506 said:

Lawton 7000

Was that the one for sale awhile ago on sd, if it is, it's shame it's broken already as it looked a cracking rifle.

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I had a problem using 24grns of N135 in my .17Rem, batch loaded in the March to the existing spec which had been working fine year round for a few years.

I must have put around 20rounds through the  rifle over the months without a problem til the August when I zeroed another scope to it.... first shot, stiff bolt lift....second shot, stiffer bolt lift and with the third shot I had to knock the bolt handle open with the bottom end of a club hammer shaft. No noticeable increase in recoil or much change in the poi.

The cartridges are stored in a room that doesn’t get any sun and I hadn’t left them in the sun beforehand....strange one.

Pulled the rest of the batch, dropped to 21.5grns and worked back to 23grns where compared to an original target they were a couple of clicks off the original zero. 

Speaking to 20-250 on the SD, he’d experienced similar, unexpected results with 135 but I’ve not experienced it with N133 in the .20.

 

fizz

 

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16 hours ago, Bob57 said:

Was that the one for sale awhile ago on sd, if it is, it's shame it's broken already as it looked a cracking rifle.

It was off sd

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2 hours ago, bri2506 said:

It was off sd

👍 , Get it fixed mate, and back to the beginning with load development, just FLS every time, and you should have no problems, and ask if you want to know anything, there's quite a few on here shooting 20 practical.

 

 

 

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Cheers that's the plan. Just on with ordering a fl Redding s type so I can do it in one die. 

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