300 Win Mag Reloading with Superformance and 175gr Sierra TMK (tipped match king)

DISCLAIMER/WARNING FOR NEW RELOADERS:  Any load data in this article is for ONE particular rifle (mine).  If you try this load in your gun, it may not feed and worse, it may feed but blow up your rifle causing injury or death. Be very carefull when extending your Cartridge Length over the reloading book published values as there can be dangerously huge increases in pressure. 

I finally received a box of 175 TMK direct from Sierra and couldn't wait to do some more experimentation in my 300 win mag. I know these were mostly made to be a 308 match bullet but I figured the 300wm might like it just as well.    If you have been following this blog,  I bought a Savage 110 FCP in 300 Win mag and have experimenting to find a good load for this rifle.  I have more than 10lbs of Superformance on hand and have been trying to see if I can come up with a long range load using it.  There is little load data on the Superformance still and I think a lot of people are afraid to experiment with reloading.  I have yet to use magnum primers with the superformance but those experiments will be coming soon as well. For now, i have been using CCI #34 and CCI 200 primers. I switched from the #34 to the 200's because I think the #34s tend to hide the early signs of overpressure.  For example, I was seeing ejector marks before I was seeing primer cratering or flattening. This is because the 34 is a much harder primer designed for Semi-autos. I digress.

After determining my max OAL  for this cartridge which wsa 3.612 (on the lands), I decided to start with some longer bullets and some max "magazine" length loads (the longest load that fits in my magazine.

RANGE REPORT

The following were shot in 5rd groups at 100yds.

COAL	POWERCHARGE	AVG FPS	AVG GROUP SIZE
3.595	74gr	3120	.937"
3.575	74gr	3100	1.25"
3.500	74gr	3090	1.25"
3.500	75gr	3115	.625"

These bullets seem to have a lot of potential in the rifle. I only loaded 5rds of each so the data is really only a starting point. One thing I noticed is that really all loads worked well. The speed was consistent and I believe the rifle cooling in between groups is why we didn't see much change between the 74gr load and the 75gr.

I was happy to finally have an accurate load which actually fits in the magazine. These TMKs  have a sufficiently high BC at .545 and I believe I could load these quite a bit hotter. I would actually like to see how these do around 3200fps. According to the Hodgdon Ballistic Calculator at 3200fps we would see a ballistic chart like the following:

The chart doesn't differ much if you input 3100fps as velocity.  At 1500 yards, the velocity is 1128 vs 1164.  I really don't plan on shooting much past 1000 yards with this rifle so really this is quite good.  The next step for me is to load up a bunch and shoot some 10 and 20rd groups to see if this is really the load I want to settle in on.

More to come!

300 Win Mag - Superformance - 208gr Amax - Playing with C.O.A.L (cartridge overall length)

Playing with case overall length

DISCLAIMER/WARNING FOR NEW RELOADERS:  Any load data in this article is for ONE particular rifle (mine).  If you try this load in your gun, it may not feed and worse, it may feed but blow up your rifle causing injury or death. Be very carefull when extending your Cartridge Length over the reloading book published values as there can be dangerously huge increases in pressure. 

If you have been following this blog, you may have seen that for other than the SIE HPBT 155gr,  and 175 TMK,  accuracy has been dismal so far with this bullet powder combination in my rifle.  Before I give up, I decided to play around with the COAL and see if things improve (usually they do).  I took a measurement using the loose bullet technique . This is where you take a fired case and lube the neck, put a bullet in seated just enough to hold it in the case and then put it in the gun and close the bolt. It may take a bit more effort to close the bolt but shouldn't be forced.

If you find you are exerting a lot of effort, you probably made the mistake of using a resized case (resized neck is tighter) or you forgot to lube the inside the neck. 

Another approach you can use is to just seat the bullet in a resized (unprimed) case and try to close it in your rifle. If there is any resistance, seat the bullet a little lower and try again. Keep going until you are able to close the bolt on the cartridge will little or no resistance. This should be close to your max overall length.

The first method will put you just over the max oal (lands tend to dig into the bullet and you definitely don't want to load at this length). I usually back off this .010 and then color the bullet with a dark sharpee (see picture right) and put it in the gun again to see if it makes marks on the bullet ogive.


If it does, I back it off another .010 and try again. I generally repeat this process until I can close the bolt on a cartridge without leaving marks on the bullet ogive. For my Savage 110 FCP, this measurement was 3.635".  I then back off another .010 and use that as my starting COAL. My max COAL I record at 3.640 which is the length where this bullet would be lightly touching the lands. I always record this info in my reloading notebook since this process is a pain to repeat.

I loaded 10rds at 3.625 which is way over my magazine length (3.510).  I wanted to try a light load and a heavy load so I used my min (66gr) and max (72gr) from my previous test results. I expected that the velocities would be lower since I was seating the bullets out quite a bit (creating more capacity). 

Next I wanted to load to the max length that would reliably work in my magazine.  I again made 10 rds at min and max powder charges using the COAL of 3.500. 

RANGE REPORT

Things started off a bit rough as I my first 10 shots proved to be a  WTF load.  This is to say that groups were just over 4". Here is the data.


PPU 3x fired brass neck size only, Superformance, CCI #200, 208gr AMAX

5 shot groups fired at 100 yards

COAL	POWERCHARGE	AVG FPS	AVG GROUP SIZE
3.500	70gr	2800	4"
3.500	66gr	2550	2.25"
3.500	68gr	2700	2.15"
3.600	70gr	2905	1.5"
3.615	70gr	2750	2.25"
3.615	71.5gr	2850	1"

In summary, the trend I noticed was that as I increased the OAL , accuaracy seemed to get better however, if velocity was not above 2800, accuracy was degraded. The best load which was with 3.615" COAL and 71.5gr Superformance showed a little sign of over pressure. There was some slight cratering on the primers on about 3 out of 10 shots.

Here is a picture of those 3. You will notice a little cratering on the primer strike and some light circles on the "300" from the ejector.

For now I am done playing with this bullet powder combination.  I didn't seem to have much success without overpressure.  The 208gr amax seems to do better around the 2900 - 3000fps mark and I just can't get there safely with superformance.  I have had great results with superformance and 155s and 175s however and you can read about that in my other blog posts.

Experiments with 300 win mag and Superformance - 168gr amax & 155gr SIE HPBT

DISCLAIMER/WARNING FOR NEW RELOADERS:  Any load data in this article is for ONE particular rifle (mine).  If you try this load in your gun, it may not feed and worse, it may feed but blow up your rifle causing injury or death. Be very carefull when extending your Cartridge Length over the reloading book published values as there can be dangerously huge increases in pressure. 

I decided to give the 208gr amax a break for a weekend and try something different. I have a bunch of 30cal bullets on hand which I reload mostly for 308 and 30.06 and thought I would give some a try.  I decided to do some minimal loads and see what velocities I got.

Again because superformance has a similar burn rate to Winchester Supreme 780 and I had load data for that powder (courtesy of Hodgdon Reloading Center) and used the minimum charge as the starting point.

I tried two loads this time out. The first was with Sierra 155 MK HPBT.
I used 75gr of Superformance which according to the load data I had, should generate velocities between 2900 - 3000fps. Again I used PPU brass and CCI #34 primers.  This was the second time reloading these cases and they were neck sized only.

The second load was 168gr Amax with 72gr of Superformance, PPU twice fired brass and CCI#34.

At the range I started with the 155gr first and was completely shocked at how far off my estimates were.

Here is the data.
155GR SIE HPBT  #34 CCI  PPU BRASS  75GR SUPERFORMANCE
Shots #1-10
1. 3170
2. 3193
3. 3131
4. 3200
5. 3210
6. 3197
7. 3217
8. 3187
9. 3238
10. 3215

So after firing the first shot, and looking at the Chrony, I thought either I made a huge mistake or the Chrony was broke. I checked the brass and there was no sign of over pressure. I continued on. The group sizes for the first two 5 round groups were .9" and .7".  Now that's what I am talking about!

The next 10 produced a range of velocities between 3177 - 3211. Again great groups under 1".  This was actually a total surprise because I was pretty sure that the 155SMK wasn't really made for that kind of velocity.

Next up was the 168gr AMAX.  Here is the data:

168gr AMAX  #34 CCI  PPU BRASE 72GR SUPERFORMANCE
Shots #1-10
1. 3200
2. 3192
3. 3183
4. 3194
5. 3183
6. 3184
7. 3167
8. 3193
9. 3192
10. 3179

Again, wow.. I was expecting to be around 2800FPS but this is crazy. 3200 was way hotter than I expected. Again, the brass looked great, primers were in good shape, no signs of over pressure. The only downer was that the groups sizes were 1.8" - 2".  My rifle hated this load but I may tune it up or down a bit to see if I can get something to group.    I have a box of SMK 175 TMK coming soon so looking forward to putting those down range with superformance as well.  So far in my rifle, this stuff is turning out to be a super powder for 300 win mag (well at least in terms of velocity).

More to come!