.307, TSX and pressure issue's

[xxclaro]

I recently loaded some rounds for my .307 Winchester using 150gr TSX bullets. I had Varget and BLC-2 on hand, but could find no specific load data for the TSX. I ended up using 43 grains of Varget and 44 grains of BLC-2 . I took them out and shot them over the chrony. The Varget loads shot at around 2525 fps, and the BLC-2 about 100 fps faster. However, 2 of the 8 rounds had flattened primers, one being very flat, the other still showing a little curve at the very edge, but just a tiny bit. The other 6 looked totally normal. I reduced the load by a full grain,and seated teh bullets to minimun COL,as I've been told that X-bullets shoot better a fair distance off the lands, and seating them farther out is said to cause pressure issue's. I went out and fired 3 rounds, and again 1 of 3 showed a flattened primer. All Varget loads showed normal primers. Extraction was fairly normal, one or two maybe a bit sticky. Does anyone know why this might be happening sporadically like that? I've decided to stick with the Varget, but accuracy is not what I expected with this rifle. It's shooting around 1.5 to 2 inches, where as it usually shoots 150gr bullets easily into 1 inch. Anything I can do to try tightening them up a bit? Shots can get a bit long out here, I'd like to feel confident out to 300 yds if possible.

[flatnose]

I cant say anthing for the TSX, but in theory BLC-2 has a very similar burn rate to that of W748. Winchester reloading info states 44grns of W748 powder as max load for a 150grn bullet. Out of my rifle I get 2525fps with that load, and very good accuracy. The bullet is seated out almost all the way to the lands.
Seating your bullet deeper in the case will give you more pressure. I would reduce the load to 40grns of BLC-2, and work up from there. As you are having primer problems at 43grns, I would call that the absolute max load.
Varget is a slower buning powder than BLC-2, so at 43grains it will have less velocity and pressure.
I have found that case life with full loads in the 307 is drastically reduced with max loads. I have noticed variable pressures required in seating the primers. p.s. I use winchester standard large rifle type and not the magnums. Chech the case neck tension. The necks harden up real quick. I anneal the necks after 2 shots, as I have had some split. Some of the brass for the 307 is not of the best quality. Made in CHINA perhaps?
I would feel confident using the w748 load out to 300yds for accuracy. Velocity isnt everything or even that important in most situations.

[flatnose]

OK. just did a quick bit of research. TSX= solid copper.
There lies the problem.......maybe.
Copper is less dense than lead. Therefore the copper bullet will have to be longer than the lead/jacket bullet of the same weight. Hence the higher claimed BC. of the TSX bullet. ( at what velocity this BC is claimed at I do not know).
The longer TSX bullet will most likely have a larger bearing surface in contact with the rifling.
Also if you use the same OAL for both types of bullets, The copper one will be taking up more powder space, as it is longer. This will cause higher case pressure. The longer bearing surface will also contribute to higher pressure.....more bore contact=more friction=more pressure.
I had often thought about this when previous posts had mentioned alternative materials for bullets. The conclusion I came up with, is that all rifles to this point were designed to shoot reasonably accurately with lead bullets. The balance of twist rate/cartrige design/bullet design, all play an important part.
Off the top of my head, I cant think of any match or benchrest shooters that use anythiong other than lead or lead jacket bullets.
As a possible suggestion, I would think that the slower powders such as Varget, IMR4064 etc may work better for your application, and with experimenting more I think you will find an acceptable level of accuracy. I would also explore the possibility of using the faster BLC-2 loaded to lower velocities in the 2300fps to 2350fps range.
Hop[e all this helps. Good luck.

[TedH]

My limited experience with monolithic bullets has been that a rifle may shoot them at least as well as any other bullet, or they won't shoot for beans no matter what you do. You also need data that is specific to that bullet. When I was developing loads for a 338 Win and a 300 Win, Barnes said to seat the bullets .050" off the lands. That's been a few years ago, and the TSX bullets may be different. Shoot Barnes an email for load data.

[xxclaro]

Thanks for all suggestions thus far. I did email Barnes, and they had nothing for me,said they had no data for .307, so I guess I gotta keep testing. I'm looking forward to trying this bullet on deer this year, should be interesting.

[Nath]

BLC2 needs a mag primer really, I had similar problems as you describe with it and one day will try again with a mag primer.
I recently learned to full length resize my 30/30 brass to make sure the locking bolt rises all the way consistanly. It was not before untill I added 3/4 turn more on the sizing die!

Nath.

[buckeyeshooter]

If you are using the tsx, try cleaning your bore with barnes copper cleaner. Copper bullets can act wacky if there is any lead in the bore. Barnes always recommends .050 off the lands as was mentioned and the copper bullets do have a longer length and larger bering surface as mentioned. You may have to experiment with them to find the correct combo. Which is not a good thing at a buck a bullet. Are these the flat nose or spitzer bullet design?

[El Chivo]

you may have less pressure with the Barnes than with lead, since there's less surface area touching the barrel, due to the several grooves cut into the bullet. The grooves also give the copper that engages the rifling somewhere to flow to. In general Barnes says load with more powder than normal, not less.

I did some testing with the 30-30 version and they do seem to zip right out of there.

Check out the FAQ's, also they have a DVD which I got with an order of bullets, busting all these bullet myths.

[Nath]

They probably don't obturate even!

Nath.