308 Winchester Berger 200.20x N150

[jtigertic]

I did a little research before I decided to ask for some advice here. I am wanting to put together a load for 308 Winchester with Berger 200.20x and N150 just looking for some start loads and an idea of where the max load would be. I am loading these a little short currently about .030 off the lands at 3.100 I wanted to try to find an accuracy load and then play with a little seating depth. Anyone able to help me out here ?
Thanks

 

[TexasC]

What brand of brass? Primer pocket LR or SR? For regular LR primer load somewhat lighter, use VV data,
This time of year pick the warmest day possible, think +70s. I will be doing much the same shortly. I am thinking to start with VV N550 ( new manufacture ) temperature stable. Good Luck! Be safe!
TexasC

 

[Precisionhunter417]

Start with 42 grains and work up in 0.3 until you see pressure signs. Then back down 0.4-0.5 for safety. Been my experience you will be very happy with small primer brass and cci 450 primers.

 

[jtigertic]

I am using Peterson Small rifle primer brass for these.

 

[RegionRat]

For what it is worth, here is the VV published data for perspective.

 

[jtigertic]

I am assuming most people have had better ignition with the magnum small rifle primers vs the standard ? I have been loading 45gr of IMR 4350 with the standard small rifle primers with very accurate results but at 2453fps on avg. I have heard of people running a bit faster like roughly 2600 fps while holding consistent velocity with the N150 so I ordered an 8lb can to try it out.

 

[bpd459]

Good day,
I made the change to N-150 from Varget 14mo ago, with the B200-20x, Lapua small primer brass, CCI BR-4. My Varget load was 43.3gr / 2641fps MV. My N-150 load is also 43.3gr / 2638fps MV. 30” barrel. N-150 SD’s are close to 1/3 of the Varget loads.

 

[RegionRat]

I am assuming most people have had better ignition with the magnum small rifle primers vs the standard ?

The BR4 and CCI 450 are certainly worth a try.

 

[Precisionhunter417]

I did a little research before I decided to ask for some advice here. I am wanting to put together a load for 308 Winchester with Berger 200.20x and N150 just looking for some start loads and an idea of where the max load would be. I am loading these a little short currently about .030 off the lands at 3.100 I wanted to try to find an accuracy load and then play with a little seating depth. Anyone able to help me out here ?
Thanks

Im assuming with your COAL that you are not running a standard throat on your chambering. With that being 0.170-0.180” instead of 0.090” like a standard 308 winchester you will have the room for the charge ive listed. Please confirm.

 

[memilanuk]

For what it is worth, here is the VV published data for perspective.
View attachment 1608440

2.795", with a 20X?

That sounds like someone let the computer model generate the load data, rather than having a hooman actually do it.

 

[jtigertic]

Im assuming with your COAL that you are not running a standard throat on your chambering. With that being 0.170-0.180” instead of 0.090” like a standard 308 winchester you will have the room for the charge ive listed. Please confirm.

Throat was chambered at .165 freebore

 

[Laurie]

2.795", with a 20X?

That sounds like someone let the computer model generate the load data, rather than having a hooman actually do it.

It also means the data are useless in all practical terms. I don't understand why companies do this.

 

[memilanuk]

2.795", with a 20X?

That sounds like someone let the computer model generate the load data, rather than having a hooman actually do it.

And to further illustrate the point... that is a 20x seated to 2.795“.

Besides the bullet taking up an absolute ridiculous amount of case capacity, the bearing surface is below the case mouth (the Sinclair comparator is loose/rattling).

 

[RegionRat]

2.795", with a 20X?

That sounds like someone let the computer model generate the load data, rather than having a hooman actually do it.

Yup, hard to understand why some companies publish models instead of test bbl data.

Curious since you have the stuff at hand, what rough overall length is it when the boat tail junction sits just above the neck-shoulder junction the way most of us would load in 308W?

 

[memilanuk]

Yup, hard to understand why some companies publish models instead of test bbl data.

The entertaining part is when they come on here and swear on a stack of bibles that it's not computer generated.

Curious since you have the stuff at hand, what rough overall length is it when the boat tail junction sits just above the neck-shoulder junction the way most of us would load in 308W?

These are seated +10 thou past touch...

 

[Monte F]

The entertaining part is when they come on here and swear on a stack of bibles that it's not computer generated.



These are seated +10 thou past touch... View attachment 1608677

This is close to what I have with a new barrel chambered with the 2013 FTR reamer. I have 3.119" at .015" jump. The barrel that came with the rifle was 3.083" at .015" jump, unsure which reamer was used. The previous owner was shooting 185 Juggernauts which I loaded to 2.974" at .015" jump. I think the 2.795" is magazine length, which is not a concern in F-TR single loaded.

 

[Acyr]

Start at 42.0 with CCI 41 or 450 and believe what the target tells you.

 

[RegionRat]

A notional load run at the 2.795" OAL

And a notional load run at 3.120" OAL with the same charge ladder as above. Due to the extra case volume opened up by not seating so deep, the pressure/velocity goes way down.


Then by taking the above advice and loading to nearer the usual levels, we get back to a more realistic level. Here is the run for 43.3 grains. Predicts roughly 2370 fps at 54ksi, which is pretty close to what @bpd459 was showing.

 

[memilanuk]

Here is the run for 43.3 grains. Predicts roughly 2370 fps at 54ksi, which is pretty close to what @bpd459 was showing.

Other than being a couple hundred feet per second slow...

For whatever reason, N140 / N150 are two powders that, in my experience, you really cannot use the default Ba values in either QL *or* GRT; both will severely underpredict the actual MV using the OEM data. Ya kinda have to do some rest runs, and true up the model with reality in order to get predictions that make any kind of sense.

FWIW, I'm running @ 43.2gn N150, in a 28" HV, and getting around 2570 fps... and that's the *slowest* dang 20X load I've ever had. Any more and I get clickers (with Alpha OCD SRP brass)... I'm thinking it's more a chamber/die/brass fitment issue than actual over pressure, but it shoots well enough that I really don't want to mess with it too much

 

[RegionRat]

Yup, both the powder parameters and the case volume need to be trimmed up to get more exact match-up to results.... but I don't even bother with trying to get those models to an exact match.

I just use them for a rough view and then focus on what the targets are telling me, however I don't play with the edges of the pressure on the high or low ends. I am just not a fan of redlining the brass or the rifle.

I have friends who shoot F-T/R in 223 who step on it really hard, but they are very experienced and accomplished shooters who know full well what playing at that pressure level means. That just isn't me.

I do like to play with overbore wildcats, so the QL and GRT models help when there is no such thing as a load manual.

BTW, the above were for a short 20" standard 308 bbl, when using a Palma or F-T/R bbl that velocity goes up to more like 2598 fps which is close to BPD459"s 2638 fps. Without a trim on the case volume and powder batch, I would call it close enough for government work. Confusion was my fault for being too lazy to paste another screen. I still agree with the idea that you would want to trim values and temperatures to sharpen the pencil.