210 BERGER BC AFTER POINTING

[TonyR]

Hi JB.
I was hoping you might jump in here since you started me down the road to confusion on this stuff with your article.

Jeff has raised some interesting possibilities with regard to what I've observed. Everything I've talked about in this thread has been based on hundreds of 6mm VLDs fired out of my 6mm BR. Lately, I've been working up loads with the 139 Scenars for my 6.5x284 and I have just assumed that the BC effect would be the same as for the 6mm BR since it's not hard to burn out a barrel testing a 6.5x284. However, Jeff's point about the bullet seater plug and its effect on the hollow point is interesting because I have had a difficult time getting concentric loaded rounds,meaning under .001 inches bullet runout) with the 6mm BR and the VLDs unless I straighten many of them. And I've tried everything in the way of neck-turning and custom sizing and seating dies but I still have to straighten most of them. They shoot fine after I straighten them, but that can take as long as the rest of the process combined. I sure was pleasnatly surprised when nearly all of the 139gr Scenars came out of a standard Redding Competition seater under .001 inches bullet runout. I'm going to have a close look at what is inside the hollow points of some of these bullets I've been shooting.
I'm going to be doing a lot of load development for a straight 284 when I get the barrels back later this month. I am having them throated for the 180gr Berger VLDs so that might give me a chance to test a lot of these possibilities, particularly the drill gage sorting. I only did it once to convince myself that the investment in the trimming and pointing gear might be worth while.
I've really enjoyed this thread. Thanks to everyone for their thoughts.

 

[JHardy]

I have closed the meplats on roughly 5000 187 BIBs. When you start with a bullet as good as the BIB, you really don't have to sort. The Junke gives you no help on these fine bullets.

Having said that, closing the meplats on the BIBs gives a little more BC -- which is nice -- but closing the meplats also uniforms and improves an already uniform BC. How do I know? From testing on the target from 600 to 1000 yards.

Joel Pendagraph,sp) has shot the 187s great at Hawks Ridge. He VERY slightly uniforms the meplats. David Tooley has also shot the BIBs very well. David inserts points to improve and UNIFORM the BC. Both techniques are improvements on the UNIFORMITY of the BC.

I have now closed the meplats on between 25,000 and 30,000 bullets since the development of the meplat closing die in 2002. In that regard, I have never seen any bullet/load combination that could not be improved at 1K with closed meplats. Everything else being equal, I have also found closed meplats give you the uniformity of the clipped meplat but with an improved BC.

When you shoot long range prone or F-Class prone, sometimes you end of waiting longer that you would like,often) for the target to come out of the pits. You better have wind reading skills and you better not have vertical from variations in BC.

When I was shooting 1000 BR with some of the best in the world at Hawks Ridge, I NEVER saw anyone READ the wind like we have to do in long range prone and Palma. Most light gun 5 shot groups would be concluded in 15 to 20 seconds or less. Heavy gun 10 shot groups would sometimes be done in 30 seconds. A very quick long range 20 shot string with sighters will take you 10 minutes. A fast F-Class string will take around 5 minutes with good pit service. These would be very fast strings. There can be a WORLD of difference in conditions in that time period vs. 30 seconds in a condition window.

The name of the game in 1000 prone or 1000 yd BR is accuracy, combined with high and consistent BC, yielding waterline vertical.

I will make a bold statement that I don't think anyone can disprove: "After you have established your best load with a given bullet, closing the meplats is the most significant thing you can do to improve your 1000 yard on-target performance." You can't make chicken salad out of a chicken #$%^ load, but you can improve your best load, and that is all you can ask.

It is not just my opinion, it is an absolute fact.

Jim Hardy

 

[eddyverhoeven]

I have been following this discussion for a while and to some extent, it has been an eye opener for me. I wonder if it would be worthwhile to uniform/point the meplats for use at shorter distances as I am mainly a 300 meters,+/- 330 yd.) prone competition shooter.

Happy New Year to all

Eddy

 

[MOTORSPORTS55]

I brought this topic up to help me with improving my group with my 300 wsm with the 210 bergers at a 1000YDS . I was not pointing yet but was gong to give it a try should i try pointing the bullets first or got right in to trimming and then pointing ?

The reason i brought the question up about the bc difference was if i point my hunting bullets the 210 bergers and 338 match kings how far off would my click chart be off and how would i correct it with out spending a ton of time shooting to see what was gong to change ? Or may be i should not even worry about pointing my hunting bullets !

thanks for all the info gays

Shawn

 

[JHardy]

Shawn:

If you have a pointing die for your 210s and 338s, you may or may not want to close the meplats on your hunting rounds. Unless you were really doing long range varmint work etc., I don't think you could see the difference. However, it takes so little time to close the meplats that if you enjoy the loading and prep process as I do, why not?

Favor Center,
Jim

 

[Bryan Litz Ballistics]

Tony,
Thank you for taking the time to explain your testing to us. From your test results and careful statistical analysis, I agree with your conclusion that there can be more BC variation within a box than I originally thought. My assessment given in a previous post was about +/- 1% of BC variation within a box, which for your application,6BR w/ 105 VLD's) which would produce about 4" of vertical at 1000 yards. Your careful test results suggest roughly double that, indicating perhaps up to +/- 2% variation, maybe a little more.

As I stated earlier, the objective of my testing is to quantify the average BC as accurately as possible. I usually don't focus on the shot to shot variation, so my assessment of +/- 1% was not based on facts as hard as yours. Your observations are also more aligned with the testing reported earlier by Jason Baney,Larry Bartholomew and Ken Oehler).

I thought the pointing tool was a valuable asset when I thought it only reduced vertical by 4". Your evidence suggests about double that,for your application) so that makes the pointing process even more valuable than I thought!

It's interesting to note that a given improvement in BC has more of an effect on performance for smaller calibers than larger calibers. For example, in your application,6mmBR, 105 gr VLD, G1 BC = 0.532, ~2900 fps) a +/- 2% variation in BC produces about +/- 4" of vertical,8" total) at 1000 yards. However, a +/- 2% variation in BC for a 7mm 180 grain VLD,BC = 0.659) at 2800 fps only produces +/- 3" of vertical,6" total). Still a big and worthwhile improvement, but the smaller calibers stand more to gain from the BC uniforming and improvement than larger calibers.

Thank you for sharing your enlightening test results.

-Bryan

 

[TonyR]

Thanks for your reply, Brian. I will be doing load development with the 180gr 7mm VLD shortly and it will be interesting to compare the effect with the 6mm results.

To answer Eddy's question directly, I think the effect is highly visible at 300 yards. It is just much more obvious at longer distances such as 1000 yards. Whether it is worth doing for your application is a different question. I saw my 300 yard vertical, at that time, shrink from an inch and a quarter to about three quarters of an inch while my 1000 yard vertical decreased from 17 inches to 8 or 9 inches with the 6mm BR.

 

[JHardy]

Eddy:

I have never shot 300 meter prone, but I am a long range prone shooter who looks forward to some chances to shoot 300m.

As the 300m prone target is very demanding and requires a very hard hold and exacting shot to shot discipline, I would close the meplats. My feeling is that anytime you can uniform the BC and reduce the vertical you are likely to get an extra point or X in prone competition, not to mention the fact that it should help you stay on call even within the X ring. On the 300m target, even a 1/4 minute or less difference could be critical on a given on-the-line shot when you broke center X.

For me, the bottom line is that I never want to leave a point or an X on my loading bench as these come "free" for the effort of your prep. Besides, closing meplats is basically very easy.

I know that hard holding Bryan Litz and JP shot some very nice 300 scores at the SOA this year, and maybe Bryan can comment from first hand experience.

Jim

 

[eddyverhoeven]

Many tx for the answers. I'll contact Brian

Eddy