300 WM charge weight INCREMENT QUESTION

[mark5pt56]

Getting ready to load some 300 WM for the first time(loaded other calibers)

Question is, with the capacity, do you run in 1 grain increments or do you do 1/2 grain ones?

I will be using once fired FC from A191(2900 average from my PSS) -- no pressure signs either

H1000 and WLR magnum primer, 190 SMK.

I appreciate it and if you have any "recipes" for review?

Mark

 

[Clark]

Re: 300 WM charge weight INCREMENT QUESTION

In magnum I work up in 1 gr increments until primer pockets get loose. Then I work up again in 0.1 gr increments to find the exact threshold of loose primer pockets. Then I back off a couple grains and call it a useful load.

 

[EXSOCAL]

Re: 300 WM charge weight INCREMENT QUESTION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body">In magnum I work up in 1 gr increments until primer pockets get loose. Then I work up again in 0.1 gr increments to find the exact threshold of loose primer pockets. Then I back off a couple grains and call it a useful load. </div></div>

Shouldnt you be looking for other signs like flattened primers. hard bolt lift, etc waaaaay before the primer pockets are loose? Also, I may be wrong, but loose primer pockets are more a function of repeated reloadings as opposed to immediate over pressure.... hmmm....

 

[mark5pt56]

Re: 300 WM charge weight INCREMENT QUESTION

I always look for the other signs as I start from/close to the bottom. I just did a test on the .308 after starting up loading again(more time than money, had it all packed up when I had more money than time)
I went off Lee and Hodgdon info with start 42, max 45 at first. I went to 44.5 which was the most accurate but the primers were flat, nothing else though. After talking with Sierra, I went back and did a round with 41-43(they list 36.? to 41.7) in 1/2 increments and settled on 43 which happened to chrono yesterday the same as factory Black Hills. Primers look good, no other issues, real happy since I have Dope on that BH round in both sticks. The 43 was a tad more accurate than the 44.5, it's cool now and no need to play at max, especially when it gets warm about here.

I ask about the 300 WM since the percentage of change with it's volume if the 1/2 grain affects it as much.

Mark

 

[scifri44]

Re: 300 WM charge weight INCREMENT QUESTION

I always do half increments , but I'm always higher in pressures than what the books say. Here's two load that I worked up that shoots best out of my 300WM. And also, be aware that Accurate Arms has discontinued their 3100 power , which sucks because that shot well with my 190 MK . Definitely look for any signs of pressure, and good luck with everything !

Remington 700 Police 300 WM

26in factory barrel with vais brake
1-10 Twist

RP brass
190 MK
Fed 215 Large Magnum Primer
75.0grs of AA3100 at 3115 FPS
Trimed to 2.600
C.O.A.L 3.600
.5 MOA at 100

RP brass
Hornady 208 Amax
Fed 215 Match Large Magnum Primer
72.0grs of IMR 4831 at 2940 FPS
Trimed to 2.600
C.O.A.L 3.578
.25 MOA at 100

 

[bohem]

Re: 300 WM charge weight INCREMENT QUESTION

I base my increments on the relative charge weight range being tested.

A 223 has appx 40% of the powder that a 30-06 does so if you use a 1/2gr increment to get close in a 30-06 it is entirely possible to miss the range on a 223.

Therefore I do this:

Appx powder charge range * 1% = rough increment

Use the rough increment over 6-8 increments and you should have little trouble finding a node region and also you can work up to pressure signs usually.

Then my fine increment is 1/4 of the rough increment

For a 300 WM with 75gr of powder in the case it would be:

75gr*0.01=0.75gr rough increment

Fine increment = 0.75/4 ~0.2gr

It has worked equally well for me from 222 Rem through 338 Lapua Mag.

 

[Clark]

Re: 300 WM charge weight INCREMENT QUESTION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SOCAL</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body">In magnum I work up in 1 gr increments until primer pockets get loose. Then I work up again in 0.1 gr increments to find the exact threshold of loose primer pockets. Then I back off a couple grains and call it a useful load. </div></div>

Shouldnt you be looking for other signs like flattened primers. hard bolt lift, etc waaaaay before the primer pockets are loose? Also, I may be wrong, but loose primer pockets are more a function of repeated reloadings as opposed to immediate over pressure.... hmmm.... </div></div>

For 6mmBR, yes, primer trouble precedes primer pocket problems.
For 300 Win Mag, no. Different case head design. The 1925 300 H&H case head has the primer pocket as the weak link.

Flat primers do not matter.
Pierced primers matter. In magnums, if the primer pieces before the primer pockets get lose, that is an indicator for a problem action. Either too much fire pin protrusion or poor firing pin to firing pin hole fit can cause that.
Stiff bolt lift before lose primer threshold would be an indicator for a problem action. Bolt lug dents into lug abutments could cause that.

The load threshold of loose primer pockets in one firing if not far from the load that makes lose primer pockets in 5 firings.

Waiting for primers to fall out is inaccurate like hanging chads.
Measuring insertion force of next primer is much better.
Measuring the extractor groove growth around 360 degrees before and after firing is even better.

 

[EXSOCAL]

Re: 300 WM charge weight INCREMENT QUESTION

Learn something new every day!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SOCAL</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body">In magnum I work up in 1 gr increments until primer pockets get loose. Then I work up again in 0.1 gr increments to find the exact threshold of loose primer pockets. Then I back off a couple grains and call it a useful load. </div></div>

Shouldnt you be looking for other signs like flattened primers. hard bolt lift, etc waaaaay before the primer pockets are loose? Also, I may be wrong, but loose primer pockets are more a function of repeated reloadings as opposed to immediate over pressure.... hmmm.... </div></div>

For 6mmBR, yes, primer trouble precedes primer pocket problems.
For 300 Win Mag, no. Different case head design. The 1925 300 H&H case head has the primer pocket as the weak link.

Flat primers do not matter.
Pierced primers matter. In magnums, if the primer pieces before the primer pockets get lose, that is an indicator for a problem action. Either too much fire pin protrusion or poor firing pin to firing pin hole fit can cause that.
Stiff bolt lift before lose primer threshold would be an indicator for a problem action. Bolt lug dents into lug abutments could cause that.

The load threshold of loose primer pockets in one firing if not far from the load that makes lose primer pockets in 5 firings.

Waiting for primers to fall out is inaccurate like hanging chads.
Measuring insertion force of next primer is much better.
Measuring the extractor groove growth around 360 degrees before and after firing is even better. </div></div>

 

[mark5pt56]

Re: 300 WM charge weight INCREMENT QUESTION

I loaded up 3 each of 74-78.5 in .5 increments. I hope to try some tomorrow. Not sure if I will get through all 10 groups though.

 

[mark5pt56]

Re: 300 WM charge weight INCREMENT QUESTION

Well, I loaded one each of 71, 72 and 73 mainly to be on the safe side and to check the chrony/foul the bore.

Once fired FC(A191) H1000 3.34 coal 190 smk

Fired three each at 100

cloudy, 42 degree's, DA -600

74, average vel was 2808, group .765
74.5 average vel was 2834 group went to 1.16
75 average vel was 2885 group went to 1.065
75.5 average vel was 2892 group was .795
76 average vel was 2915 group was close to 1.5, Primers started to crater
76.5, fired two, stopped, was getting ejector swipe, vel was 2972/2962, two I fire were at .750

Don't know if I was imagining it, but the gun felt "different" on the 76/76.5.

I chrono'ed 6 A191 the other day and they were 2899/2892/2899/2875/2886/2927

Overall, not bad I guess, worked a safe load and I'm glad I did the .5 grain increments on this as 77 would have been a bit much. Glad I have the RCBC puller!

First I've really shot a 300 WM, seems that marksmanship errors show more, especially NPA. Recoil is really not an issue as some make it, I don't "feel" a big difference.

Mark

 

[shoot4fun]

Re: 300 WM charge weight INCREMENT QUESTION

Uh, are you happy with that level of accuracy for three shot 100 yd groups? I would not be.
I am currently running 67 gr IMR4350 with 190 SMK and hitting 2975 FPS with 5 shot 100 yd groups coming in at just under 1/2".

 

[mark5pt56]

Re: 300 WM charge weight INCREMENT QUESTION

Of course I'm not "happy" with it, I know I can do better shooting than that. I could always try different powders, etc and even knuckle down with fundementals to tighten it up a bit.

I know stock guns are capable of great accuracy and some are not.

I'm happy from the standpoint of making some decent and safe ammunition for a new rifle and caliber though.

In the big picture-on my worst day if they're under an inch, I'm not beating myself up over it either, knowing I have good days and get them all touching or even close to a one holer.

 

[Grumulkin]

Re: 300 WM charge weight INCREMENT QUESTION

Just a few observations:

1. I'm on the side of those who don't think working up to loose primer pockets is the way to go. If the load loosens the primer pockets on the first firing, whatever the case, it's either way too hot or the brass is way too soft.

2. For him who said his loads are usually of higher pressure than listed in a manual; I would ask, how do you know? Unless you have pressure measuring equipment which most of us reloaders don't have and which all publishers of manuals do have, you don't really know.

3. Using some percentage based on case volume isn't a bad idea in deciding on load increments but I'm not usually so precise. For cases the size of the 308 Winchester, I work up in 1 grain increments until I'm approaching maximum published loads and then I go up in 0.5 grain increments. Be advised though, that in the 300 Win. Mag., unless you go back and do further testing on either side of what you think the best load is, you could miss the sweet spot using 1 grain increments.

How wide a range the sweet spot occupies, depends on the powder. In some powders, like H4831SC in my 300 Win. Mag., the range seems pretty narrow. In my 7mm Rem. Mag. using RL-22, the range seems very wide.

4. In strong modern firearms, I only need a starting point in load workup; I can figure out what the maximum load should be all by myself. Usually, my load ends up being under published maximums but occasionally it will be over a bit. I do not use a chronograph to determine pressure since I think it's very unreliable for that use. Usually, in load work-up, groups will tighten up to a point and then start to widen again. I stop where the groups are tightest regardless of the velocity. My 300 Win. Mag. load comes in about 2,850 fps using 200 gr. Accubonds and is good for less than 1/2 MOA (testing with 3 shot 100 yard groups), deer, raccoons, etc.