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300 Win Mag

24 Apr 2019
@ 12:10 pm (GMT)

Douglas Wood

Hello folks. Lurked here for quite a while. This may actually be my first real post. Live in Wisconsin,USA. I have the reloading, long range shooting and bolt action accurizing books so far in the series. Great reads and reference. Love shooting and reloading. Been at it since I was 12 or 13. Started out with a 243Win. Great gun and still have it.

On to my situation. I got a very lightly used barrel from my cousin and changed out my Winchester M70 in 338 Win Mag to a 300 Win Mag. Had it professionally done at the most reputable gunsmithing company we have here. They checked headspace after installing the new to me barrel. Got it back, reglass bedded the stock and began to work up loads. I will primarily hunt deer, with the occasional elk hint thrown in. I know I'm over-gunned, but I like the combination.

Started loading 165gr Hornady SST bullets and a hand full of 200 g ELD-X. I have an F1 chrony to test my speeds. I am a bit perplexed at my results so far. I'll start with the 165. I am competent at reading pressure signs, and thus far I have exceeded the max loads with very little signs of excessive pressure. I have stopped loading higher at this point. What is confusing is the speed I am recording. My last 3 shots were 3550fps exactly. Book says 3200 fps at max load. Up to that point I was getting spreads of and where from 35-70fps. This load what I am calling max has the best spread. No powder compression, but there isn't any space left behind the bullet. I am seated a long way from the lands... .097". I had to do this due to magazine length, something I hope to change. But my question is speed alone enough to worry about pressires? There are no ejector swipes, blown primers or the like. The primers are Winchester magnum, as are the cases. Winchester I read has soft primers, and yes they are flattening out. NOT squaring off flat by any means. Am I pushing this too far? The temperatures were in the 60s and sunny, so relatively warm.

Next the last two 200 gr8 ELD-Xs have shot 2995 and 3056 fps. I am still below published max by 2 gr. Forgot to mention RL-22 for both bullets. Neither of those last two loading showed high pressure signs either. Max speed from the published data on the 200 is 2900.

So, either my chrony is way off, or??? Any helpfully advice?

Replies

25 Apr 2019
@ 07:28 am (GMT)

Nathan Foster

Re: 300 Win Mag
Hi Douglas, it may just be a chrony issue. It will be best to check the angles of the chrony next time you set up and make sure it is a good 13 feet from the muzzle. It can also help a great deal to test the chrony with another rifle / cartridge of a known velocity or test your rifle over another chrony if using a shared range. Sometimes a chrony will play up around noon when the sun is shining from directly behind you. On sunny days, you'll get your best reading at around 9-10am and again in the late afternoon provided there are no shadows.

Yes, the Win primer will flatten right out if pushed even a little bit too far, giving a good warning that you need to back off. I take it the primer pockets are still fairly tight. As you say, you have been reloading for a long time now, you know the drill here.

Yes, its normal to be off the lands by a long way when using the standard Win Mag chamber and a 150 to 168gr tipped bullets, whether by mag limitations or the fact that you simply cannot get close without having the bullet seated too far out of the case neck.

Every once in a while it is possible to come across a very fast barrel but it is rare to find one that yields an extra 300fps. It can happen, but can also be a sign of poor bore tolerances so do pay attention to accuracy while testing as this will also offer clues.

You don't have to justify your magnum or any mistakes made here. It's good to be able to work through this. Keep at it.

As an aside guys, I will launch the reamer blog once David Manson arrives back from his current break. I will put this into PDF format so that you can save and the refer to the specs later. On the Win Mag, we have changed the measurements quite a bit. I did not want the long jump that Douglas mentioned above and spent a great deal of time on the math with David, working out how to keep it short but without losing power. Ultimately, the test rifle (Grant Lovelock / True-Flite barrels) gave 2950fps with the 208gr and is grouping inside a half minute so it was a definite win, 90fps faster than I was expecting. The max OAL for this upcoming batch of reamers is approximately 91mm / 3.583" with the 208gr. This and other OAL's will be in the PDF for future reference.
25 Apr 2019
@ 10:55 am (GMT)

Douglas Wood

Re: 300 Win Mag
Thanks Nathan for the response. I am used to the Win primers flattening out. I have seen where I would get ejector marks which is usually where I back off. Yes, primer holes are tight. New cases. I haven't started looking for the accuracy yet since they were new cases. Wanted them fireformed to my chamber. I am nearing completion of the 100 cases. Might load a few mild loads up tonight and get through a few more. Light conditions were good. No overhead direct sun. I think I was a bit too close to the chrony though, as the muzzle blast did knock the shields off after every other shot. I was maybe 10' from the end of the barrel. Well, time to load a few up and go shoot. Too windy to go for any accuracy tonight. But it is great practice since making changes to the trigger. I reworked that as well with the build. Got it down to about 2# by changing the spring to an aftermarket. Very nice trigger compared to when I started. It was about 6#!
29 Apr 2019
@ 09:14 am (GMT)

Douglas Wood

Re: 300 Win Mag
So I started working a load spread from73 grains to 77. Still under the published max for the powder (RL22). Best group so far is .63" @ 100 yards. That was at 76.5 grains. I made sure the chrony was set up correctly. Chrony is set at 15'. I am getting 3370-3379fps on that load. I'll work around that load now and possibly tighten that group up I hope.

Next I have a spread on the 200g ELD-X bullets to try as well.
14 May 2019
@ 01:03 pm (GMT)

Douglas Wood

Re: 300 Win Mag
Well best group I get is .77" @ 100 yards. Settling on that for now and will play around now with the seating depth. Average speed with 9 rounds was 3329 fps on the 165.

200 gr was .85" @ max load. Going to back off that however since one it was max load and two I started seeing some pressure signs on the second fired cases. Average speed on those was 3178. Best group was .44 @ 2800 fps. I'll play around the slower group.

05 Jun 2019
@ 02:59 pm (GMT)

Calvin Nickel

Re: 300 Win Mag
Sounds like you have one of those mythical and much desired “fast barrels” - they do indeed exist, don’t know what the explanation is. What twist rate? If it’s a 10 you really owe it to yourself to try the 208 or 225 eld match.
09 Jun 2019
@ 01:03 am (GMT)

Douglas Wood

Re: 300 Win Mag
It may very well be, but if it shoots fast and I can't hit anything with it I might as well use it for a concrete stake. I did do a check against a known velocity cartridge. My 243 with superformance loads tested 3083 average. Nathan States 3115 with a 22" barrel. I think that's well within what should be expected. I haven't had much time lately to shoot, but what little I have the loads where I got good accuracy have since opened up to 1.5" or so. So I figured it was time for a thorough cleaning. So today if I have time I'll check some more. Have half a dozen foulers loaded and some more test rounds. Finally a day without wind that should be a solid test day.
09 Jun 2019
@ 07:30 am (GMT)

Nathan Foster

Re: 300 Win Mag
Hi Douglas, I just want to check - is this a fluted barrel from the Extreme model M70? If it is the Extreme model, it may have swollen at the flutes allowing the higher velocities but without any accuracy. This is a common problem on the modern lightweights with fluted barrels but still relatively unknown among end users.

Regarding the mag box, if yours has the block in it, just drill out the spot welds, then file and sand the burrs, no need to try and re-weld any joins or holes. This wikll allow you to get close to the lands with the ELD-X but not with the 208gr ELD-M if you ever try it. The ELD-M will of course be much closer than with the block fitted to the mag box.

You're doing OK, working through it one step at a time.
09 Jun 2019
@ 03:40 pm (GMT)

Douglas Wood

Re: 300 Win Mag
Calvin, forgot in the last post. It's a 1:10 barrel.

Nathan, not a fluted barrel. I finally got a reasonable load for the 165 SSTs today. Loading 78.0 grains of RL22. I've got a .8" group at 100 yards. Velocity is averaging 3488fps. For the distances I shoot (<500 yards) it will be good till I have more time to devote.

As for the 200 ELD-X. Nothing great to report yet. 1.5" best. So I broke open a stash of IMR 4350. Loaded up a few rounds to try tomorrow. I may just blast the remaining 200s off and get some of the 208 match bullets. I know I'll find the sweet spot eventually.

As far as length to the lands, the closer I got the more the group's seemed to open up. I may have a concentricity problem. Need to set up a jig and the dial indicator to find out.

One more potential holding me back is my scope and aged eyes. I have an old Leupold 3x9 scope that got sent back to the factory and reworked. It's fully capable, but I'm finding my eyesight may require a little more magnification! Oh the joys of getting older.
10 Jun 2019
@ 11:11 am (GMT)

Douglas Wood

Re: 300 Win Mag
Well, switching powder made a difference! I finally have a decent load for the 200 ELD-X. It was gusty today so probably not the best day to be testing for accuracy. I found a load that gives me less than an inch. I loaded around it and all opened up. Went back to it and again under an inch. So I'll play around with other variables based on that load. It happened to be .4g less than max load. I averaged 2883 fps with it. That's about 100 fps more than book says for the load. I'd like to play with seating depth next, but I need to figure out whether I have a concentricity issue first. All my previous loads where I seated towards the lands yielded worse results. So now I need to decide if I stick with the ELD-X or got to the 208 match. I have just a half dozen bullets left in the bin. That being said I won't be able to do further testing for a couple of weeks. Gives me time to pick up moresupplies.

Cheers!
Doug
10 Jun 2019
@ 11:16 am (GMT)

Douglas Wood

Re: 300 Win Mag
I quoted the wrong speed. It was actually 2929 fps! So definitely over what the book says.
13 Jun 2019
@ 12:45 pm (GMT)

Douglas Wood

Re: 300 Win Mag
Nathan I took your advice and drilled out the spot welds on the spacer in the magazine. Worked like a charm! So question. I think I know the answer before asking. Should I leave the 200 ELD-X on the back burner for now and check out the 208 ELD Match? Maybe I should explain my interest first. I have the 165 SST for a close to medium range for deer. I wouldn't mind using the 200-208 at range, but more just want that load for elk. I know both are a little heavy for deer. The 165 should do great though. Being this barrel appears to be performing really well. So I think I should step up to the 208. Opinions?
14 Jun 2019
@ 03:35 pm (GMT)

Hamish Gibbs

Re: 300 Win Mag
Hey Doug, the cartridges book is an awsome resource for the queries you have, I mostly have experience with the 208 amax(eld m) at a mv of 2750 on lightweight game at relatively close range. Impressive performance and from what I've seen if you had to pick one projectile for everything you mention it would be hard to go past.
14 Jun 2019
@ 03:56 pm (GMT)

Douglas Wood

Re: 300 Win Mag
Hamish, I have the cartridge book. I reread the section tonight. Not sure how I missed it. I'll be picking up some 208s on Saturday!
16 Jun 2019
@ 12:43 pm (GMT)

Douglas Wood

Re: 300 Win Mag
Picked up the 208 ELD match pills today. Well, best group so far is just under an inch. Average velocity is 2975. Still have a bit of room to work up. I tried .025" off the lands. Hoping I get some more shooting in tomorrow between rain storms.
28 Jul 2019
@ 01:11 am (GMT)

Paolo Consalvi

Re: 300 Win Mag
30-06, Sierra #2165, N160. Bullet kiss the lands.
Headspace 0.05 mm, groups 0.35 MOA or better.
Try Sierra on your big 30.
28 Jul 2019
@ 03:57 am (GMT)

Douglas Wood

Re: 300 Win Mag
It's in the plans. Currently the loads I have will suffice for the short range I need to shoot, 250-400 yards max. I also just got some more 150gr Hornady interlocks to try for rebate. When I burn all these up I'll be looking to Sierra next, possibly Speer. Both have done great in the past for me. I have a shine to Hornady and usually exhaust all options before turning to other options. Just really like the terminal performance of Hornady. They seldom seem to disappoint me. It just seems I have to play a lot to get the right combination.
28 Jul 2019
@ 09:01 am (GMT)

Paolo Consalvi

Re: 300 Win Mag
I know the Speer 200 but it is flat base.
In the original barrel, with long throat, it is was good
to obtain a long cartridge. In the new barrel, the leade is
zero and the OAL is short.
Sierra #2165 is 35 mm length ( Cb 0.56) and is good with 11" twist. Low run-out.
Disappointed with eld-m 195, secant ogive (?).
Sierra or Speer are tangent ogive. My reamer has 1:22' chamfer
Hope it helps.
Regards,
 

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