270-300 Win Mag now feasible

[CogburnR]

I just load in 1g increments and look for grouping in the series.

Say I start with 72g of powder...

72g, 73g, 74g, 75g, 76g. So I am looking for pressure, speed, and grouping. Say 72g is low pressure and 73g is better but a half inch closer to the bull. then 74g is a cloverleaf with 73g and better speed but no pressure, then 74g is better yet and in the group with the previous 2, then 75g is a little out and starting to get hot and 76g is out of the group and it is too hot. This tells me the powder charge for the optimum barrel time is probably in the area of 74g(an accuracy node).

I test a few powders and the best ones shake out pretty quickly, the nodes for each powder will stand out. These nodal areas should not show sensitivity to slight powder charge changes for grouping. So far for my rifle this looks like 75g Retumbo with the 165 Matrix(3160fps), RL33 possibly at around 83g(3220fps?) and 73g(2900fps), H1000 at 74g(3100fps). Rl26 and 7977 did not show good grouping in the pressure series which may mean the nodes for these powders are not in the area of the pressure series so they may not be useful.

While doing the above RL33 produced a .24" group and Retumbo a .44" group with the powder charges 1g apart.

Once I find a node in the powder and speed/pressure I am looking for with good accuracy I will try to tune out ES and shrink groups using bullet seating depth and powder increments if needed.

If the ES is good with the Retumbo or RL33 load I will just load that.

I am now at a round count of 48 in my barrel including 15 rounds of gong banging. 5 rounds for each powder(RL33 twice because I started too low). 3 rounds of the best RL26 for verification that I didn't screw up the groups.

 

[Big Jake Duke]

That sounds like a great system. I think now that this thread has some data a guy can use that and shorten his load development considerably.

One of the self imposed issues i have had is that i wanted to test this round with multiple weights and manufacturers of bullets. The closest thing to it is a 270 weatherby or a 7mm Jarret, i figured it would be in there somewhere, so i started with weatherby info and explored.

I also had this barrel nitrided before i put it on. It was chambered, threaded and headspaced, then unscrewed and nitrided. Nitriding an AR or AR 10 can let the barrel last 10,000+ rounds. And those guns rend to run hotter than my bolt action. So i plan to use this barrel until my wheels fall off. So round count is more of an expense than an accuracy degredation on this rifle at this time.

But i am glad we have you in the group!

 

[jhfleming]

That sounds like a great system. I think now that this thread has some data a guy can use that and shorten his load development considerably.

One of the self imposed issues i have had is that i wanted to test this round with multiple weights and manufacturers of bullets. The closest thing to it is a 270 weatherby or a 7mm Jarret, i figured it would be in there somewhere, so i started with weatherby info and explored.

I also had this barrel nitrided before i put it on. It was chambered, threaded and headspaced, then unscrewed and nitrided. Nitriding an AR or AR 10 can let the barrel last 10,000+ rounds. And those guns rend to run hotter than my bolt action. So i plan to use this barrel until my wheels fall off. So round count is more of an expense than an accuracy degredation on this rifle at this time.

But i am glad we have you in the group!

Thanks, BJG!

Question about the nitride it penetrates the surface of the steel and hardens it right or is it a heat dispersion benefit? Like hard anodizing does to aluminum. I assume it was applied to the bore as well?

The OCW will work with any manufactures bullets of the same weight just rerun the final charge weight test to verify, that should suffice.

I understand why you used the ladder method with a new wildcat there is no historical data to allow you to use the OCW method.

Thanks for doing all the testing for use and sharing your data.

 

[270DT]

This is with the 270-300WM with a 26" Pac-Nor super match barrel, my loads so follow at your own risk.

Tried VV 570N with the 140 Accubonds with Fed 215. This powder is a VERY large stick powder, largest I have ever seen.

My other MAX load with H1000 was 77 grains at 3,339 fps. With this load the bolt was sticky and realistically too hot to use for safety purposes. I found that with VV 570N I had right at an additional 100 fps increase for the same charge weight. My MAX load with sticky bolt with VV 570N was also 77 grains at 3,427 fps.

The safe load for 140 Accubonds with H1000 was 76 grains at 3,274 fps and with 76 grains of VV 570N I had 3,349 fps.

I did not shoot for accuracy but VV 570N appears to be hanging right in there with everything else and looking good so far.

I also tried US 869 with the 150 Woodleighs and I think it is just too slow for my setup and accuracy wasn't there compared to everything else. I only loaded up to 80 grains and I did not have any pressure signs. Velocity at 80 grains was 3003 fps. There is definitely room to go up but not sure if I want to because the accuracy didn't appear to be there with this powder for me.

I do want to try RL33 with the 150s and see where that gets me. Will try that next.

I believe I am pretty much settled in with the following loads for now, not sure with my 26" barrel I can better these. I am using this rifle for hunting and looking for flat trajectory plus accuracy.

130 Swift Scirocco 68 grains of IMR 4451 at 3,410 fps

140 Nosler Accubond 76 grains of VV 570N at 3,349 fps

150 Woodleigh PP 76 grains of Retumbo at 3,211 fps

So far I have fired 53 rounds through this rifle, doesn't seem too bad for load development.

 

[270DT]

I also wanted to say that it appeared VV 570N ran a little "cooler" and I didn't see the barrel heat up I have seen with the other powders but it was only 52 degrees here this morning when I was at the range.

Also wondering what you guys thought about running full loads on just 300 WM brass sized to 270-300 WM and not fire formed? I really don't want to fire form every piece of brass initially to save barrel life but will if you guys think safety may be an issue. Also interested to see if there is a difference in accuracy.

 

[jhfleming]

I also wanted to say that it appeared VV 570N ran a little "cooler" and I didn't see the barrel heat up I have seen with the other powders but it was only 52 degrees here this morning when I was at the range.

Also wondering what you guys thought about running full loads on just 300 WM brass sized to 270-300 WM and not fire formed? I really don't want to fire form every piece of brass initially to save barrel life but will if you guys think safety may be an issue. Also interested to see if there is a difference in accuracy.

Not sure if it's a safety issue but it is 1 factor affecting accuracy. Best reloading guide I have found is "Precision Shooting - Reloading Guide-", ISBN # 1-931220-12-3, unfortunately it is out of print. It recommends seating the bullet lightly against the lands, and do not load more than a medium amount of powder.

 

[Big Jake Duke]

The nitriding cover all surfaces, that is why a barrel must be finished and indicated before it is nitrided. It cant be worked on afterwords without wearing out tooling.

You also do not nitride an action, it seems to react different to diffferent types of metals and i have been told that it could weaken an action.

I am not a metalurgist, just trying to relay the information as i understood it.

 

[Big Jake Duke]

I also wanted to say that it appeared VV 570N ran a little "cooler" and I didn't see the barrel heat up I have seen with the other powders but it was only 52 degrees here this morning when I was at the range.

Also wondering what you guys thought about running full loads on just 300 WM brass sized to 270-300 WM and not fire formed? I really don't want to fire form every piece of brass initially to save barrel life but will if you guys think safety may be an issue. Also interested to see if there is a difference in accuracy.

I have been simply necking down 300 win brass with one pass and loading it 100%

Head space is on the rim.

 

[Big Jake Duke]

Had a shoot out today between the two best (accuracy) acceptable hunting velocity loads and in my rifle the 75grs of Retumbo is king.

Now i will mess with seatind depth to try and fine tune it.

In my 243AI, SHOOTING 105 Bergers, the difference in group is dramatic with seating depth. A 4/100 difference is either clover leave or 1 1/4 inches!

So as is the 270/300 is shooting 9/16". I Hope to improve that or make it more consistant thru the seating process.

3245fps

 

[270DT]

This is with a 270-300 WM, 26" barrel with my loads so follow at your own risk.

Back to the range this afternoon.

My rifle is really liking VV N570. Tried it with the 150 Woodleigh PPs. Previous top load was with 77 grains of Retumbo with stiff bolt and extraction at 3,299 fps. This load is realistically too hot to use and not safe. A usable load of Retumbo at 76 grains I was at 3,211 fps.

With VV N570 I went up to 76 grains and a velocity of 3,355 fps with no pressure signs. I ran out of time but would expect to hit pressure at or around 76.5 or 77 grains. Accuracy also still looking promising with this powder. So far with it I have exceeded my previous 140 grain and 150 grain loads by approximately 100+fps each. Now I am wondering what it will do with the 130s.

I also tried the 130 grain Barnes TTSX with IMR 4451. I had to seat this bullet a little deeper than the 130 grain Swift Scirocco just by the design of the bullet. I hit pressure signs at 66.5 grains at 3,353 fps. This was about 100 fps slower than I got with the 130 Scirocco before hitting pressure signs.

Be awhile before I get back to the range but I will give the 130s a try with the VV N570 just to see what it can do.

 

[Big Jake Duke]

From what i could find, the burn rate on n570 is very close to h870, which rumor has it it very close to US 869.

That gave me all the best loads except for the berger. It was faster and very accurate. The Berger 170 with that powder in that gun gave me nightmares.

Good luck.

 

[270DT]

BJD from shooting the 150s, N570 is no where as slow as US869. I would like to try some AA8700 but haven't found it on a shelf anywhere. I loaded a set of 130 TTSXs last night with N570, will let you guys know results compared to the IMR 4350 burn rate powder I was working with.

 

[Big Jake Duke]

BJD from shooting the 150s, N570 is no where as slow as US869. I would like to try some AA8700 but haven't found it on a shelf anywhere. I loaded a set of 130 TTSXs last night with N570, will let you guys know results compared to the IMR 4350 burn rate powder I was working with.

I just got it off of this scale-

http://www.lapua.com/upload/reloading/reloadingburningratechart2011.pdf

 

[TXAoudadKlr]

Slight derail but would VV N570 be suitable for a big 30cal?