QL Request for .270 WSM 140gr Nosler BT Retumbo R-P Case 2.85 OAL

[Heavy Barrel]

Could someone please run the following through QuickLoad?
Is it common for book velocities to be as much as 300fps slower than real velocities?
My intuition is telling me that something is off though I'm not quite sure what or where.


Cartridge: .270 WSM
Case: R-P
Projectile: Nosler BT 140gr
Primer: WLRM
Powder: Hodgdon Retumbo
OAL: 2.85"
Barrel Length: 24"
Case Capacity: 80.9gr H20

Per Hodgdon's and Lyman's data the starting load for this is 68gr and the max load is 71.5gr, I started out with 67.5gr and increased in .5gr increments ending at 72gr. With the starting load per Lyman I'd expect velocities in the upper 2900fps and Hodgdon is saying just over 3000fps, I was already getting velocities over 3250fps. By the time I got halfway up the ladder I was getting flattened primers and early signs of cratering around the firing pin, at that point the average velocity was over 3300fps.

Case Bullet Bullet WT Primer Powder ChargeWT COL Min Max Avg Spread Std Dev R-P Nosler BT 140gr Fed 215 Retumbo 67.5​ 2.85​ 3234.4​ 3283​ 3254.9​ 48.6​ 18.5​ R-P Nosler BT 140gr Fed 215 Retumbo 68​ 2.85​ 3269.3​ 3294.7​ 3284.6​ 25.3​ 9.3​ R-P Nosler BT 140gr Fed 215 Retumbo 68.5​ 2.85​ 3283.2​ 3314.1​ 3294.3​ 30.9​ 10.5​ R-P Nosler BT 140gr Fed 215 Retumbo 69​ 2.85​ 3305​ 3325.9​ 3316​ 20.9​ 8.1​ R-P Nosler BT 140gr Fed 215 Retumbo 69.5​ 2.85​ 3299.6​ 3344.6​ 3322.1​ 45​ 22.5​

​

 

[SJB358]

Just my opinion but I disregard max charges listed mostly and use my chronograph to tell me what my gun, lot of powder and bullets are doing. I do pay attention to max speeds and load accordingly. Looks like your case either has more volume capacity or a tighter chamber. I wouldn’t sweat it and back your charges down or adjust to fine accuracy. My WSMs have made 3250’ish give or take with most 140’s without too much strain.

 

[Heavy Barrel]

Just my opinion but I disregard max charges listed mostly and use my chronograph to tell me what my gun, lot of powder and bullets are doing. I do pay attention to max speeds and load accordingly. Looks like your case either has more volume capacity or a tighter chamber. I wouldn’t sweat it and back your charges down or adjust to fine accuracy. My WSMs have made 3250’ish give or take with most 140’s without too much strain.

I appreciate your input...I agree with the possibility of a tighter chamber.

I cleaned the barrel between the other two loads I tested that day, one with the same bullet/brass combination but using MagPro and Fed 215 primers per Nosler's published data. Because of the great Nosler bullet shortage of early 2020's I put together a load based on Hornady's published data using their brass and140 SSTs with H4831 and WLRM primers. Both of these loads the velocities ran just under the published data and not once were there any early signs of excess pressure even with loads that ranged from .2gr to .5gr over max.

 

[SJB358]

I don’t put too much stock in cratered primers and even sometimes marks on cases if it’s a first firing since brass needs to expand to fit a chamber. I think you’re in good shape if you observe what the chrono says within reason to your barrel length. Pressure is speed and vice versa. Unless you have a pinched neck from too long of brass or you’re shooting a bullet with a lot of bearing surface compared to the book loads you’re likely in fine shape.