300 Win Mag Load Input

[jzimmerman]

I have a Remington 700 5r Gen 2 I’m using at 100yd


Nosler brass

Federal 215M primers

Hornady 212gr Eld-X

3.606” COAL

0.020 off lands


I tried developing a load using IMR 4350 because I have a ton but I did load a few with IMR 8133. The 8133 loads are definitely compressed. Where should I go from here?

 

[GoldieMI]

are these Target rounds?
how far are you intending to shoot?

 

[jzimmerman]

Eventually move out to 1000+ looking for input on picking a charge, seating depth etc

 

[GoldieMI]

interested in if you kept a picture of the overall target so you can see if the POI moves from the POA as you increase the charge?
68.5 looks good in absence of information - but if the 69.5 and 70.0 grain are more flat for Point of Impact, then you might have a node to play with and can tighten that up with seating depth.
at 1000 yards the SD will come into play as well...assuming no chronograph data?
if that makes sense

 

[jzimmerman]

interested in if you kept a picture of the overall target so you can see if the POI moves from the POA as you increase the charge?
68.5 looks good in absence of information - but if the 69.5 and 70.0 grain are more flat for Point of Impact, then you might have a node to play with and can tighten that up with seating depth.
at 1000 yards the SD will come into play as well...assuming no chronograph data?
if that makes sense

yeah I still have the target up and can measure the POA vs POI. I didn’t start chrono yet as I’m more worried about accuracy than speed. I do feel I was getting a bit higher pressure out of the 4350 vs the 8133.

 

[GoldieMI]

look at the consistency of the POI to find where they are not changing...then I would go down a few steps and up a few steps from there...that way you know the vertical is not from changing POI...it would be either your velocity/load consistency or shooter input to the gun.
that is how I do it anyway...find the area in the loads where it's shooting to the same POI and then narrow down the charge weight from there..once that is known, then I play with the seating depth to further tighten it.
Once it's promising, I start taking it out to distance as what works at 100 yards doesn't always work for long distance.
The Chrono data will help with developing your drop for further distances...

 

[KYregular]

How long are you allowing barrel to cool down between shots?

 

[GoldieMI]

I tend to do 5-6 minutes between shots on my 300WM. It helps with my suppressor as well to reduce mirage.

 

[jzimmerman]

Goldie each of those groups pictured has the same point of aim and all shot off a lead sled. Any up and down in a group movement was from load consistency. The 68.5 of 4350 and the 79.5 of 8133 are looking like two good candidates. Someone on another forum suggested I do the Berger seating depth test before messing with charge weights more.

 

[GoldieMI]

You absolutely can do that. the 68.5 group looked good to me. The main reason I questioned if the 68.5 was moving the POI was because of the 68.0 and 69.0 group differences...if the 68.5 shot to the same POI as 69.0, I think that is a good place to start. However, if the 69.0 and 69.5 shot to the same POI in relationship to the POA, while the 68.5 was different, me personally (my 2 cents here) I would look into that range more to narrow it down.

 

[jzimmerman]

You absolutely can do that. the 68.5 group looked good to me. The main reason I questioned if the 68.5 was moving the POI was because of the 68.0 and 69.0 group differences...if the 68.5 shot to the same POI as 69.0, I think that is a good place to start. However, if the 69.0 and 69.5 shot to the same POI in relationship to the POA, while the 68.5 was different, me personally (my 2 cents here) I would look into that range more to narrow it down.

The 68 and 68.5 were both ≈ 6” below point of aim whereas 69, 69.5, and 70gr were all ≈ 5” below. Now the 8133 all groups were a pretty uniform 5” below POA. I will also say the higher loads of 4350 were showing impressions of the ejector on the brass.

 

[GoldieMI]

with that information...I would look into the 8133 groups as they were uniform shift - same approximate POI pattern, and didn't show ejector swipes.
I might even test a couple .2/.3 powder groups below and above 79.5 to verify no issues and then go to the Berger Test with your winning group.
you might find the overall pattern is a wide plateau for your combination.
My H1000 loads are a bit pickier.

 

[jzimmerman]

Everyone says H1000 and Reloader 22 but I had a pile of 4350 and 8133

 

[dh1633pm]

Funny, I have the same rifle. I loaded a few with AA4350. I haven’t developed a load for it. Just did 20 for break in at the middle of high and low from the Hornady manual. Used 168 grain SMKs because that is what I had. They shot well.

 

[GoldieMI]

sometime in the next few workups- I'm going to try SW4350 out as I bought a pound to play with. Never tried the AA4350 or the IMR 4350 in 300WM
H1000 and Retumbo were always available and known recipes....like H4350 and 6mm Creedmoor.