CarbonSix 1:8 or Proof 1:9

[mt100gr.]

Regardless of what I had/have available, when I do it again or rebarrel, I will go with another 300 WinMag. The new cartridges just don't deliver enough additional anything to be attractive to me unless I decide to step up to a RUM.

I consulted Broz and some others prior to finalizing with travis at rbros and my 300 has been excellent.

28"/1-10 twist/ 215s @ 2985 (H1000 with 215m) with good numbers and excellent accuracy. I'm approaching 800 rounds on this barrel and hoping for that many again.

I'll probably go carbon next time but I likely won't even consider a different cartridge.

 

[Vandy321]

Broz, what are you seeing for barrel life with 300 WM running 215s at 3k FPS over n570? I’d think it would be notably reduced from a low 2900 FPS h1000 load.

Happy 300wm owner here as well. Shooting a 26" proof right now at 2975fps. Dont quote me on this as fact, but I believe Paul up at Mile High is a big 300wm guy and was seeing over 2k rounds as well at similar speeds. He talked me out of the 30 nosler for that exact reason.

 

[tm7554]

To be shot out at 600-700 rounds seems drastic. Are the RUMs even doing that to throats that fast?

 

[Broz]

To be shot out at 600-700 rounds seems drastic. Are the RUMs even doing that to throats that fast?

I am not alone either Ryan Furman's 30 N barrel went south at 700. Others have reported similar results. The 300 RUM's I have toasted go between 800 and 1000 but have substantially more performance.

Are we seeing a pattern here? Do longer cases and friendlier shoulder angles direct flames farther down the throat? Only time will tell but I have both eyes open on this.

 

[ckleeves]

I think N570 is more to blame then shorter cases and shoulder angles. I’m betting in a 300 wm, which would be running higher pressures for equal velocity as a 30 Nos will toast throats just as fast or faster.


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[Broz]

I think N570 is more to blame then shorter cases and shoulder angles. I’m betting in a 300 wm, which would be running higher pressures for equal velocity as a 30 Nos will toast throats just as fast or faster.


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I am not going to argue that a powder that creates more velocity does not shorten throat life. And I have not stated the shorter case or sharper shoulders are the sure culprit either. But it is something we can watch, and that is my intention. It was stated long ago that the flame patterns from improved (sharper) shoulders can and do direct the flame pattern closer to the case mouths. Pretty easy to see that. But again I subscribe to the old saying "Speed Cost Money, How Fast Do You Want To Go" theory.

What supporting data do you have that a 300 win mag running at the same velocity, with the exact same charge weight as a 30 Nosler would be running at higher pressure? I have always found pressure is pretty lineal to velocity. Especially with equal length barrels, same bullets and same charge weights. Case capacity of these two is a very moot point as well in this case. I am always open to learn from supported data. Please share.

Thank you
Jeff

 

[ckleeves]

I guess I don’t see how pressure is linear to velocity. Let’s take a 6.5 creed and a 6.5 prc. A 40k psi load in the prc generates the same velocity as a 60k psi load in the creed. Exaggerated example but you get the idea.

If your loading the same exact load then the less voluminous case will have more pressure.

I think your running the absolute hell out of a 300 wm to top 3k with a 215. I have played with 3 different WM’s all chambered with a JGS RM reamer and not one has made it to 3k. 2860-2930 is what I have found in all of them. My current one I have ran up to 2960 at max but it’s pretty rough on brass so I’m back down at 2900.

I have a barrel sitting here for a 30 nos but haven’t gotten it together yet. But from the others I have seen they will top 3k in crap Nosler brass. N570 is a no go for me. Seen guys report bad erosion in throats as early as 200 rounds in other chamberings.

It may or may not kill throats but barrels are a little expensive for me to find out.


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[Vandy321]

I guess I don’t see how pressure is linear to velocity. Let’s take a 6.5 creed and a 6.5 prc. A 40k psi load in the prc generates the same velocity as a 60k psi load in the creed. Exaggerated example but you get the idea.

If your loading the same exact load then the less voluminous case will have more pressure.

I think your running the absolute hell out of a 300 wm to top 3k with a 215. I have played with 3 different WM’s all chambered with a JGS RM reamer and not one has made it to 3k. 2860-2930 is what I have found in all of them. My current one I have ran up to 2960 at max but it’s pretty rough on brass so I’m back down at 2900.

I have a barrel sitting here for a 30 nos but haven’t gotten it together yet. But from the others I have seen they will top 3k in crap Nosler brass. N570 is a no go for me. Seen guys report bad erosion in throats as early as 200 rounds in other chamberings.

It may or may not kill throats but barrels are a little expensive for me to find out.


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Iiving at 7k ft helps...I'm 1.5gr below max, zero pressure signs, currently loading 77.5 gr and hitting 2975. Being throated longer as we speak, that 77.5gr is at mag length, fully expecting to get over 3k with no pressure loaded to CIP length mags with BDL.

 

[ckleeves]

Iiving at 7k ft helps...I'm 1.5gr below max, zero pressure signs, currently loading 77.5 gr and hitting 2975. Being throated longer as we speak, that 77.5gr is at mag length, fully expecting to get over 3k with no pressure loaded to CIP length mags with BDL.

I’m at 6k so not a huge difference. What powder and barrel length are you using? I’m assuming Norma or Nosler brass from that charge weight?


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[Vandy321]

I’m at 6k so not a huge difference. What powder and barrel length are you using? I’m assuming Norma or Nosler brass from that charge weight?


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ADG brass...26" proof, 200 rounds on it, H1000

 

[Cahunter805]

3K with a 215 is a stout load but doable with a custom and properly setup Reamer. Broz has a great reamer setup!

 

[ckleeves]

ADG brass...26" proof, 200 rounds on it, H1000

Interesting. I have the same barrel and length using ADG also and I hit max at 75.5.
77.5 would be ugly in my current WM with ADG.


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[Broz]

If your loading the same exact load then the less voluminous case will have more pressure.

I think your running the absolute hell out of a 300 wm to top 3k with a 215. I have played with 3 different WM’s all chambered with a JGS RM reamer and not one has made it to 3k. 2860-2930 is what I have found in all of them. My current one I have ran up to 2960 at max but it’s pretty rough on brass so I’m back down at 2900.

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With at least two of us conducting the same capacity tests, the average case capacity difference between the 30 N and 300 win mag give the 30 N the advantage by 3.5 to 4 grains on average. I do agree with you but want to point out that this is a small difference and would be hard to see a difference unless one was compressed and one was not. Neither of mine were compressed.

I have tested dozens of 300 win mags with 215's. In 26" rifles, IE the CA Ridgeline, and we have 3 of these right now. The Berger factory ammo runs pretty close in all with an average velocity of 2880 to 2950 from barrels with 150 rounds down them. I tested 2 rounds from each of 25 boxes to arrive at this data in preparation for a match. My fastest 300 win mag that I referred to earlier ran happy at 3035 fps for 14 firings on the brass before the primer pockets were what I would call loose enough to be of concern. I shot them all 1 more firing and tossed them. I think we both know you don't get that kind of brass life by " running the absolute hell out of " it. That said I have always stated these were max loads that showed slight ejector marks but zero increased resistance on bolt lift. This rifle was a custom reamer and 28" barrel. I have made mention before that there is often more difference from one barrel to another for velocity than case design will discern. I stick by that statement as I have shot enough to know it is true. I know you have as well. With my 300 win mag of mention being a 28" tube, we can also note a 40 to 50 fps increase in velocity with H-1000 and a 215 over a 26" barrel. So if, and I dont know this, but if your rifle running 2960 was a 26", we are now over 3K and very close to my load. Again barrel differences will often make up more of the difference.

Just my personal findings. I have done my homework and I feel I have set up tested and logged data fro as many 300 win mags as most people. Surely not everyone, but many.

Jeff

Note I edited to correct some velocities I screwed up.

 

[Broz]

Interesting. I have the same barrel and length using ADG also and I hit max at 75.5.
77.5 would be ugly in my current WM with ADG.


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77 gr of H-1000 will be max with a 300 win mag and a 215 on average. 75.5 is another sweet spot for many. Powder lot differences with H-1000 can swing 3 grains easily so it is hard to compare notes.

Dan Glover of Dan's Custom Guns just finished his personal 300 win mag using his custom reamer. I will be using it too. His rifle has a 26" Brux barrel, in ADG brass with H-1000 and a 215 he as at 3020 fps and shooting ragged hole groups for 3 shots. And, his barrel has not sped up yet. Again, there are differences, barrels being a big one, that will make more difference in velocity from rifle to rifle than any measly 3 or 4 grains of case capacity or the new space age cracker jack case designs. My point is there are plenty of 300 win mags running 215's at 3K and not over pressure. Not all, but many.

Jeff

 

[Broz]

For the record too. I tested the effects of altitude on muzzle velocity. Dan Glover built me a rifle and chronoed it with a lab radar at sea level. He then shipped me the rifle and some of his loaded test ammo. I rested here on my range using both a lab radar and a Magneto speed V3 at 4125 feet asl. There was not notable difference with the MV on my tests being with in 10 fps of Dan's.

 

[Vandy321]

Interesting. I have the same barrel and length using ADG also and I hit max at 75.5.
77.5 would be ugly in my current WM with ADG.


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I'll try to find some pictures of my primers...bolt lift did feel heavier until 78.5....79 was flattened primers. No ejector marks to go off of due to bighorn action.

I'm by no means an expert, but I had a few folks shoot it at 77.5 and they agreed, no pressure signs

 

[wind gypsy]

With at least two of us conducting the same capacity tests, the average case capacity difference between the 30 N and 300 win mag give the 30 N the advantage by 3.5 to 4 grains on average.

Interesting. What brass manufacturers were used in this comparison?

 

[Broz]

Interesting. What brass manufacturers were used in this comparison?

I have compared both Nosler 30N and about all 300 win mags including Lapua. Both fired and virgin. Ryan F did a bunch results were all close to 3.5 to 4. The largest gap may have been 4.5 I really can't remember all Ryans results

 

[CCooper]

Broz,
Off topic, but the system would not allow me to send you a PM due to my lack of postings. I have been following your threads concerning 300 Win loadings and performance for some time. I recently picked up another 300 Win. in a CA ridgeline. My hunting style for elk is much like yours in the regard I never know if the shot will be close or far. For this rifle I am planning on 215 bergers. I am looking for your personal preference in scope selection for a 0-1200 yd. gun. Quick pop shots will be taken under 100 yds at times in the timber. I prefer the CA ridgelines for the weight, but my others always seem to eventually wear Xtreme hardcore gear rings and 1-piece bases along with a minimum of 14 power scopes. Viper HSLR's currently. Budget is open to $1500 or so. never liked Nikon's. I believe your animal count and knowledge to be some of the best on here concerning the .30 caliber. Any thoughts are much appreciated.

 

[Broz]

Broz,
Off topic, but the system would not allow me to send you a PM due to my lack of postings. I have been following your threads concerning 300 Win loadings and performance for some time. I recently picked up another 300 Win. in a CA ridgeline. My hunting style for elk is much like yours in the regard I never know if the shot will be close or far. For this rifle I am planning on 215 bergers. I am looking for your personal preference in scope selection for a 0-1200 yd. gun. Quick pop shots will be taken under 100 yds at times in the timber. I prefer the CA ridgelines for the weight, but my others always seem to eventually wear Xtreme hardcore gear rings and 1-piece bases along with a minimum of 14 power scopes. Viper HSLR's currently. Budget is open to $1500 or so. never liked Nikon's. I believe your animal count and knowledge to be some of the best on here concerning the .30 caliber. Any thoughts are much appreciated.

I would sure look for a good used Nightforce NXS. Like new units sell for around $1600 Another option would be to wait for the release of the Nightforce NX8 F2. Not sure where their price point will be, but it could be close. Thanks for the kind words.
Jeff