Interesting reloading 300 wm issues

[captdan]

I've been trying to narrow down my grouping on my Accuracy international AXMC. The over the counter hunting loads produced decent groups of 3/4" or so, but I'd like to see better.
My reloading dies came in a few days ago and I loaded some 178 eld hornady match with 72.5gr of re22. I used the book Col of 3.340. I was able to produce 1/2 min groups of 4 rounds with that load.
In the mean time a friend and I did a jam fit. We averaged 4 fits for a total advetage length of 3.539. I made 15 rounds at a col of 3.428. I shot those today and the group got wider at about 1.25". I've now loaded 10 rounds at a col of 3.384 and will test this load sometime this week. I may wind up back to the recommended col of 3.340.
I'm curious if anyone has ran into such an issue. It would seem that the loads made specifically for the gun's chamber via a jam load adverage should produce tighter groups... ?

 

[Bart B.]

My reloading dies came in a few days ago and I loaded some 178 eld hornady match with 72.5gr of re22. I used the book Col of 3.340. I was able to produce 1/2 min groups of 4 rounds with that load.

How many 1/2 MOA groups were produced?

 

[captdan]

How many 1/2 MOA groups were produced?

3 groups, test shots.

 

[Bart B.]

Use that load.

Bullets jammed into the rifling sometimes raise pressure such that it changes where the barrel points when bullets leave.

 

[captdan]

Use that load.

A good point. I'm basically curious why that same load with a shorter col would work better. I may well wind up with that load, but my other guns after customizing loads after a jam fit tend to tighten groups, not open them.

 

[6MMsteve]

some barrels like jump some bullets like jump..in my 260AI it liked .60 jump, jam no, single shot..my 6xc does not like rdfs but anything burger shoots in .2s and .1s

 

[6MMsteve]

I've been trying to narrow down my grouping on my Accuracy international AXMC. The over the counter hunting loads produced decent groups of 3/4" or so, but I'd like to see better.
My reloading dies came in a few days ago and I loaded some 178 eld hornady match with 72.5gr of re22. I used the book Col of 3.340. I was able to produce 1/2 min groups of 4 rounds with that load.
In the mean time a friend and I did a jam fit. We averaged 4 fits for a total advetage length of 3.539. I made 15 rounds at a col of 3.428. I shot those today and the group got wider at about 1.25". I've now loaded 10 rounds at a col of 3.384 and will test this load sometime this week. I may wind up back to the recommended col of 3.340.
I'm curious if anyone has ran into such an issue. It would seem that the loads made specifically for the gun's chamber via a jam load adverage should produce tighter groups... ?

try some H1000

 

[Rdlningcltchdmpr]

A good point. I'm basically curious why that same load with a shorter col would work better. I may well wind up with that load, but my other guns after customizing loads after a jam fit tend to tighten groups, not open them.

Advice from a super expert ! Use the sharpy method, blacken up a dummy round seat it out, so as to leave Mark's then move it deeper a few times until no Mark's are being made. That will make it within a few thousands from rifling. That way every shot the bullet only moves a tiny bit and it is being guided on the rifling. Once you have this the only thing that makes consistant accuracy is powder choice and amount. Out of several different powder's , one will shine bright. I have seen it over and over .

 

[D.Stone]

Okay Captain Dan...I'm staging an intervention. You are on what is colloquially known as the "Struggle Bus".

If 300WM is your first adventure into Precision Marksmanship and Precision Handloading...you have picked a fairly difficult place to start. Both are skills in and of their own right that take patience and dedication to learn. Loud and heavy magnums are not known for being all that forgiving...even in an Accuracy International. Not from a marksmanship aspect, or from hand-loading aspect. Most of us learn on dainty little easy to shoot calibers like 308 Winchester before moving up to something big and loud.

The first thing I want you to do is purchase a Hornady Lock-N-Load Overall Length Gauge, and the corresponding 300WM case, and the micrometer inserts that will allow you definitively measure what overall length loaded ammo will touch the lands with your bullet of choice. There are field expedient methods that can be made to work as well...but they are usually not as precise, and are easier to get a false reading.

Second, I want you to get some good components that have been thoroughly tested. Get 100 cases that are all of the same manufacturer. Lapua cases would be preferred but they are only available in Berger ammo right now. Norma is what I have experience with, and have had good luck with. Get some 200+ grain bullets...the 215gr Hybrid or 220 Lapua Scenar are my preferred bullets...but I'm sure the Hornady stuff works just as well. Get some H1000 powder...it's proven for this weight class of bullets...it's not temperature sensitive.

Third, I want you to load some ammo. Load your 200+ grain bullet with H1000, and seat it 20 thousandths off of your lands. Make sure all of the charges are the same weight, and that they are not proof loads. I have a rifle with a long throat, so I am safe up 79 grains of H1000...your rifle might only be safe up to 72 grains if it is short throated. How do you tell? Well with the OAL Gauge you bought, and by working up a load in small increments.

Fourth, I want you to move your targets out further. For whatever reason...being able to see bullet holes at 100 yards through a rifle scope really mind-fucks newer shooters into shooting bad groups. Not being able to see the bullet holes at 200-300 yards will probably force you to focus more on your marksmanship process and not the results you are seeing on the target. It's weird...but sometimes it be that way.

Fifth, I want you to realize that it is entirely possible that you are the weak link in the system. Even people that have been shooting for decades still have days where they are shit hot...or shit not. There is no shame in having the balls to stop and say "this is not going well" and come back and attack it a different day.

 

[captdan]

Okay Captain Dan...I'm staging an intervention. You are on what is colloquially known as the "Struggle Bus".

If 300WM is your first adventure into Precision Marksmanship and Precision Handloading...you have picked a fairly difficult place to start. Both are skills in and of their own right that take patience and dedication to learn. Loud and heavy magnums are not known for being all that forgiving...even in an Accuracy International. Not from a marksmanship aspect, or from hand-loading aspect. Most of us learn on dainty little easy to shoot calibers like 308 Winchester before moving up to something big and loud.

The first thing I want you to do is purchase a Hornady Lock-N-Load Overall Length Gauge, and the corresponding 300WM case, and the micrometer inserts that will allow you definitively measure what overall length loaded ammo will touch the lands with your bullet of choice. There are field expedient methods that can be made to work as well...but they are usually not as precise, and are easier to get a false reading.

Second, I want you to get some good components that have been thoroughly tested. Get 100 cases tStonehat are all of the same manufacturer. Lapua cases would be preferred but they are only available in Berger ammo right now. Norma is what I have experience with, and have had good luck with. Get some 200+ grain bullets...the 215gr Hybrid or 220 Lapua Scenar are my preferred bullets...but I'm sure the Hornady stuff works just as well. Get some H1000 powder...it's proven for this weight class of bullets...it's not temperature sensitive.

Third, I want you to load some ammo. Load your 200+ grain bullet with H1000, and seat it 20 thousandths off of your lands. Make sure all of the charges are the same weight, and that they are not proof loads. I have a rifle with a long throat, so I am safe up 79 grains of H1000...your rifle might only be safe up to 72 grains if it is short throated. How do you tell? Well with the OAL Gauge you bought, and by working up a load in small increments.

Fourth, I want you to move your targets out further. For whatever reason...being able to see bullet holes at 100 yards through a rifle scope really mind-fucks newer shooters into shooting bad groups. Not being able to see the bullet holes at 200-300 yards will probably force you to focus more on your marksmanship process and not the results you are seeing on the target. It's weird...but sometimes it be that way.

Fifth, I want you to realize that it is entirely possible that you are the weak link in the system. Even people that have been shooting for decades still have days where they are shit hot...or shit not. There is no shame in having the balls to stop and say "this is not going well" and come back and attack it a different day.

Ok Stone, good points all noted. While I'm new to the 300 mag shooting I have shot and reloaded .308 and 6.5 creedmoor for sometime with success. I do know the .300 is another animal. I've been looking at the hornady lock-n-load and going to heavier bullets.
Thanks for your input. I'll get there

 

[Dgd6mm]

The archives here are full of excellent .300 WM reloading information. One guy in particular, I can't remember his screen name exactly. It is either catshooter or catfur.

I just checked, it's catshooter.

 

[acloco]

Load ladders and groups....start at 300 yards.

 

[miningshawn]

So I just fought this battle myself, in a 300WM. I got lucky.

The best way I have found to work a new load is to begin with an optimum charge weight test - after I have narrowed down a window and done my research. With a 300WM and a standard cut chamber I chose 76.5gr to 78.6gr H1000. I had a suspicion that there would be a good node between 77.8 and 78.3 based on data I have observed here in multiple threads. THESE ARE OVER RECOMMENDED MAX IN MANY BOOKS! But I am also seating ridiculously long because Rem700's are long-throated.

I am using 210gr Berger VLD's for this load. Common consensus is that Berger VLD's shoot best when very near, touching, or slightly into the lands. So I began seating 0.003 from the lands after using a Hornady Lock-n-Load OAL guage to find the lands, then used a Hornady OAL comparator to measure to the ogive. I seated all rounds from the ogive. If you haven't bought these two tools or something similar I highly suggest you invest - they pay off quickly.

The rest of the prep is sorting and weighing - I like to use brass that weighs close together in each OCW string. I only had access to Hornady brass, so I bought 100. The center 80 cases in weight were loaded for OCW, the other 20 got a 76gr load to foul and get me on paper.

This is a tough test. A 300WM has tough recoil to tame, even with a brake. With a brake and stout loads the concussion is tough to overcome. I did all of my testing at 200yds using paper plates and Lyman 1" dots. This forces me to FOCUS, and results are much easier to interpret, i.e. radial spread vs horizontal or vertical stringing.

So I got lucky. The OCW is what I had before a long-range class, so I shot it and found groups decreasing to 78.1 and increasing after. 77.5gr gave me 1.1MOA, 77.8gr gave me 5/8 MOA, 78.1gr gave me just over 1/3MOA, and 78.3 opened up to 3/4 MOA and I started to observe very light ejector wipe but good primers (CCI BR2).

So I settled on 78gr and loaded 150 0.002 into the lands. I also neck turned the once fired to 0.003 tension and tried to keep everything concentric by seating 1/3 - turning 60 degrees, seating 2/3 turning 60 degrees, and seating to depth. This turned out to be a solid 1/4MOA load that got me through the class (and out to 1400yds in 15MPH crosswind on the last day ). It was almost boringly predictable to shoot to 1000yd.

If I had time and inclination to begin again I would use ADG brass and 215 Berger Hybrids. H1000 and CCI BR2 wouldn't change. After finding the best node using powder weight I go to seating depth - normally lands, 0.005, 0.010, 0.030, 0.060, and finishing with mag-length.

I hope this helps a little, and a lot of it is probably review but a trip down fundamental lane sometimes helps.

 

[Dusty Stevens]

Im so over belted magnums. Ill throw a book load at one and go hunting but tuning one for a group, not anymore. You cant control the brass right with off the shelf stuff

 

[Bart B.]

Many long range prone matches were won and some records set with 300 Win Mags. With new unprepped cases. Loads used tested well under 1 MOA at 1000 yards.

The current 1000 yard prone record is 200-19X, 10" X ring, shot with a 300 Win Mag. With reloaded cases. I've tested 30-338 Mag new cases into 5 inches at 1000 for 15 shots.

 

[Bart B.]

After you've picked the load to test, shoot at least 15 shots per group. A 30% spread in size across several such 15-shot groups is normal.