When should I be concerned? Indicators & Hot loads

[BearClan]

I loaded test rounds for a 180 bullet. My manual states the Max load is 69.5 grains of RL19. That last two loads consisted of 3 rounds of 68.8 gr and 3 rounds 69.5 gr, respectively.

As fired off my last round of 69.5 load and noted that the bolt had a somewhat sticky lift (the two previous rounds of these loads had no stick bolt issues). I looked at the head and it had a "shiny spot" from the extractor (and so did the other 2 rounds). The primer was also a bit more "flattened" (barely noticable) than the primers from 68.8 gr load. The primer/firing pin mark also looked a little deeper for the 69.5 grn load. The velocities averaged 3007 ft/s for 3 rds of 69.5 f/s (the manual lists a max velocity of 3036 for this load) and 2978 ft/s for the 3 rds of the 68.8 grn load.

Therefore, I concluded that my 69.5 gr load was hot (4 of 5 indicators of high pressures). Unfortunately this load was by far, the best. (.8" vs. 1.55" group for the next closest).

I backed off my load to 69.0 grains. No sticky bolt lift, no "shiny" spot on head, but the primer still looked a bit more flattened than the 68.8 grn load and the primer/firing pin mark also looked a bit different (slightly deeper). I am still a bit confused by primer cratering. All my primers look cratered (a slight lip/lift at the edges - it is just that they a bit higher on the 69.0 and 69.5 grain loads). I didn't measure the velocities, but I know would not exceed the published velocities for this bullet/powder combo because the "hotter" 69.5 grain load didn't.

In summary, with 2 of 5 indicators being "positive" for a hot load, is my 69.0 grn load safe to use?

Thanks in advance

BTW - the 69.0 grn load had a smaller group (1.4"), than the 68.8 grn load (1.55" group )but not as accurate as the 69.5 grain load (.8").

 

[R Flowers]

Well, this is just my opinion, but that is what you asked for, right?

From what I gather in you post, the 69.5 grain load is indeed too hot for use in your gun. When you can feel a sticky bolt lift, have "shiny spots"
on the case head, and have flattened primers you have a "hot" load, over max for that gun.

I would recommend dropping a whole grain, down to 68.5 if you want to use that powder/bullet combination. Then you can be confident you will not have a problem with that load.

I would not be too concerned about cratered primers. (Except for the worsening of the craters with the top loads.) Cratered primers could be due to soft primer cups, an overly large firing pin hole, etc.

Each gun is an "individual" so to speak. I recently worked up some loads for a friend. He and I both own 300 WSM rifles, but to use the same powder/bullet combination I had to use 1.5 grains less powder in his rifle to avoid all high pressure indicators.

 

[rick smith]

Are you loading for the 300WSM? What barrel length is in the manual and what is your barrel length? How far off the lands are your bullets seated? Are you using the same primer/case/bullet as your manual? Warmer temps could have a negative effect on your pressures. Every rifle is different as are different lots of powder/primers/cases etc. You were wise to back off the charge, may have to go down some more if you will be hunting in warmer temps.Rick.

 

[BearClan]

Are you loading for the 300WSM? What barrel length is in the manual and what is your barrel length? How far off the lands are your bullets seated? Are you using the same primer/case/bullet as your manual? Warmer temps could have a negative effect on your pressures. Every rifle is different as are different lots of powder/primers/cases etc. You were wise to back off the charge, may have to go down some more if you will be hunting in warmer temps.Rick.

Hi Rick,

Yes, I am loading for the 300 WSM. My barrel length is 24 inches - pretty sure, but not certain (using factory Remington M700 XCR). The barrel length in the manual is 24 "(I got the load of loaddata. com, which indicates the data was from Barnes Manual #4). Primer, Case, and Case length exactly the same as listed on the website/Barnes Manual #4 - Fed 215, WIN case, Trimmed to 2.090. Bullet was the same - Barnes MRX.
I keep bullets inside my pocket, but outside temp was approx -1 Celsius (yes, I live in Canada). I guess I should back off my bullets even more.

 

[Antelope_Sniper]

A shiney spot at 32f can be hot enough to blow primers on a hot summer day...

 

[RiverRider]

Never mind---I misread your post and transposed velocity numbers in me feeble mind. :?

 

[hardpan]

Bearclan,
I get pretty concerned about hot loads. You mention a 1.4 inch group. Is this from a rest or bags, and how good is your scope, mount and trigger?

If the best that I can get is a 1.4 or 1.5 inch group, I try a different powder. Not a cheap habit, but i tend to get to some pretty tight groups.
Hardpan

PS at 0.5 inches, I call a victory.

 

[BearClan]

Hardpan,

I have since different load and OAL combinations using the MRX. of twelve 3-shot groups, only two have been under an inch. The average seems to lie somewhere between .145 to 1.70 inches.

I am shooting off bags (Caldwell). My trigger is set to 2.5 lbs (at least that is what I asked Gunsmith to set it at). However, I am shooting off "table" I found at the local dump - 2X4 legs and 3/4" plywood surface - not very stable. I am wondering how much of an affect this may be having. It is pretty muddy up here right now - snow is melting (I live in the Arctic), but once it dries, I plan on shooting off bags in the prone position.

I am shooting into a 1 inch circle pretty consistently using my .17 HMR (9/10 shots into a 1inch circle), and in tests with a dummy round loaded when I am not looking by a friend, I am not flinching (reticle stays on target - using the .300 WSM of course - not the .17 - just in case you were wondering).

In summary, I are pretty sure, but not certain, that my shooting is fine. However, I wish I had a sub-MOA gun to try. I am fairly new to reloading and shooting, so until I can't be certain that my shooting ability is the reason for the poor groups. Perhaps when I get back from the range after shooting in the prone, I will have better idea of what is happening (me, Table, or poor load).

 

[hardpan]

Bearclan,
Hard to say, but I would bet that it is not you. I don't trust factory loads much, but some are fine. The table is a concern. Other possibility is the gun barrel needs to be "broken in." and then the powder. I have one gun that took around 40 rounds to shoot well, then shot incredibly well. But my first group was around 2 inches, and my 5th group around 1 inch. My 7th group was a 1 hole group around 1/3 of an inch. No changes in the loads, shooter, or holder.

Also, I always start with a clean barrel. Not all guys do that, but I can only guarantee the barrel is the same if I clean it and it is cold. I posted the way that I work up a load in another forum. PM me if you want a direct copy.
Best,
Hardpan.