A "what causes pressure the most" question.

[trotterlg]

Book load data is good if it exists, for a 20BR there is not so much data. I went with starting at 204 Ruger max loads, and was good to 30gr. 30.5 went to sticky extraction. I fired one at 30.5 after I cut the 1 degree lead, it did not have sticky extraction but slightly tight bolt lift. I would say I gained about a half grain with the lead cut. I will probably ladder up from 29.4 in .2gr steps and see what I get. Larry

[Bill K]

Originally Posted by trotterlg

Book load data is good if it exists, for a 20BR there is not so much data. I went with starting at 204 Ruger max loads, and was good to 30gr. 30.5 went to sticky extraction. I fired one at 30.5 after I cut the 1 degree lead, it did not have sticky extraction but slightly tight bolt lift. I would say I gained about a half grain with the lead cut. I will probably ladder up from 29.4 in .2gr steps and see what I get. Larry

Be very careful, you are right in the max area and a little .1/10 tenth grain can make a big and dangerous condition. Safe is better than sorry and injured. Not worth the FPS. BIll K

[trotterlg]

It is looking like about 30 gr is max, could be a couple tenths more. 8208's claim to fame is that it is so temperature insensitive, so around 30 seems OK, I know 30.5 is a little much. I will run it across the Chrono and see what it is doing. I also have some 26gr Varmint Grenades I may load up a little higher, they are fairly long bullets so I am not sure my 1 in 12 will stabilize them. Larry

[barretcreek]

My old manual from the nukes in Pasco WA did a 'scope trace for each powder. And their conclusion was that the best load and max load for each powder & bullet combination was the one which had the smallest pressure deviation and usually that charge had the least velocity deviation. Called one of the manufacturers and asked about their "most accurate load" notation and the guy said "yeah, that's the load with the least deviation from the mean". Not necessarily the one which shot the smallest group according to Dr. Oehler's top of the line chrono.

[montdoug]

I have a fair number of zero free-bore, minimum spec tight chambered rounds and I always figure that when the chamber is tighter than a factory rifle and the free-bore is reduced to zero the published loading data is worth the same amount as the free-bore, zero!
I have a number of factory rounds such as the .17 Fireball, the .204 Ruger etc and on all of em with tight chamber and zero free-bore I get more velocity than the book says I should with less powder than the book says I need and to me that makes those rounds wildcats. I load em accordingly, I start "low" and work up slow with no preconceived plan as to where I'll end up either in powder charge or velocity. That's my 2cents worth .

[georgeld]

Something else I've spouted a few times.

You don't drive your car or truck full blast all the time. OR do you??
Why in the world do reloaders do that with their guns??

Just don't make sense to me to run them maxed out.
Sure it's good to know where that point is, but, drop it down where
there's no danger when something crops up as it surely well eventually.

[Nor Cal Mikie]

George:
I call it "wiggle room". Always leave yourself a little working room when you work up loads.
You load to the upper edge at 70*. You go shooting and it's 100*+. Then, you wonder why the bolt gets sticky and your groups are all over the place?
Brass life goes down the toilet, primers won't stay in their pockets and your bug hole maker turns out to shoot shot gun patterns?
Work up a mid range load with less powder and you're back in business.
You don't have to be fast to be accurate.
Mike

[wally bennett]

Just remember thousands of people have the same calibre as you do thousands use the same powder, bullet ,primer,s, COAL, same powder dispencer,same beam scales but nobody has your rifle or your scales they might have the same batch of powder or it could be a different lot.
I have had three lots of Viht N120 one used 10.8gr the next one used 11.4gr the current one uses 11.0gr all for the same velocity.
Think to yourself i have a rifle and componants that nobody else has so i will take advice on my starting load but start below that and work up till i get any pressure signes then back off in my case (17A/H ) 0.2grs.
If you load out to touch and then back off a bit it should lower your pressure but if you load short out of the lands and then get a good load with no pressure signes and then decide to load out to touch IT WILL INCREASE PRESSURE.
Wally

[sgtg]

For P dog loads you can be shooting at 50 degrees to 100 degrees, so I have started backing them down a little. I would get home and the primers would be mashed flat = loose pockets, cases stretched = more trimming and my 20-223 AI starts loosing accuracy when the load gets too hot. I proved that with a target on a hot day out P dog shooting and missing. I backed the load down 1.2 grains and that one in the heat works way better now. I load my coyote gun pretty hot because its usually cold heck while Coyote hunting and that is all I use that gun for. So bottom line, consider the temperature when loading, that mild load might be just right on a hot day. sgtg out

[sgtg]

Jammed, touching, jumped, The diameter of the bullet, a 105 A max is .2431 and a 105 Match burner is .2434 if I'm remembering correctly it was 3-4 ten thousandths. The fatter bullet was faster by 30-40 FPS ( more pressure) so when your at the top little things really matter. sgtg out