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Meplat trimming - worth it, and which trimmer?

I've been thinking about adding a meplat trimmer to my 600 yd bechrest reloading process. I've searched here, and on the entire net. Found some info but not a huge amount.
At 600 yards, does it help w/ vertical and overall grouping? Or is it not worth the time involved?
Here's the trimmers I've found:
Sinclair (a friend has one that he no longer uses, and doesn't like the give of the plastic body)
MCR: http://www.montourcountyrifles.com/
I found several strong reviews. Power driver accessory available. His does not have a hole allowing the chips to fall out. In an email reply to several questions, he recommends cleaning between every bullet to ensure a chip doesn't get in the way of inserting the next bullet. He blows his out with an air compressor.
Hoover: http://www.bullettipping.com/meplattrimmer_detail.asp
Steel, hole for chips to fall out, highest price, no power attachment.
Whidden: http://www.whiddengunworks.net/trimmer.html
Found a couple reviews, they recommended buying something else.

Any info from meplat trimming shooters would be greatly appreciated. Is it worth our time for 600 yards, or are factory bullets just fine? And if you have one or more of the trimmers, what do you like/dislike about each brand, and which would you buy again?
Thanks in advance.
drano
 
drano,

Jerry Tierney and Dave Driscoll carried out meplat uniforming and 'tipping' effects tests at 200 metres and 600yd on pre-sorted and batched examples of the 'old' Sierra 0.308" 155gn Sierra Palma MK (#2155) during spring and summer 2009.

The 200M tests involved two chronographs to ascertain velocity drop over the distance. The 600yd test was groups alone.

Bullets were trimmed (meplats uniformed) only, pointed only, trimmed and pointed using the Hoover tools as described on the website you show. Mr Tierney expresses complete satisfaction with both sets of tools as to ease of use and results. The pointed test bullets had two degrees of pointing applied as fully closing the tips appeared to affect accuracy adversely and 50% closure was better.

Tests were done with untrimmed/unpointed bullets as a control against the three options listed above. The conclusions were that pointing alone improved BC but not group size. Trimming alone reduced group sizes at 600yd, and surprisingly appeared to improve BC too. Doing both made the biggest improvement to both group size and BC, but only marginally to the latter - but still well worth doing for the group size reduction at 600. Calculated BC improvement was in the order of .45 increased to a little under .5 over 200 yards.

The rifle / cartridge was a 30" (Krieger) barrel Palma type rifle in .308 Win.

The testers expressed themselves very satisfied with the results and with the tools. Whether these results can be transferred to other cartridges firing 6mm, 6.5mm, or 7mm bullets that are much more ballistically efficient out of the box than the 0.308" 155 Palma MK is a questionable matter, but it obviously worked in this case.

I hope that this helps.

Laurie,
York, England
 
I have used the hoover trimmer and pointer, they work very well and produce nice finished bullets. I have not really done a back to back test my thinking is anything i can do to take variables out of things can only help, i do notice some bullets i take off a fair amount and some the tip barely cleans up. The things we do to try to hold a better water line!!
 
I do sort them first by bearing length and weight but thanks for mentioning it in case i wasn't.
 
Thanks to everyone for your replies.
So am I reading correctly that to get an even depth of cut, I must first sort for bearing surface, and then meplat trim in those lots, and adjust the cutter as I move through the sorted lots to maintain a similar trim amount?

Does the big hole on the top/bottom of the Hoover body do a good job of letting chips out? MCR's youtube video recommends cleaning the body w/ a que tip between each bullet, which seems to create a slow trimming process.

Thanks again for the above post info, and I'll continue to welcome more comments.
 
Laurie said:
The conclusions were that pointing alone improved BC but not group size. Trimming alone reduced group sizes at 600yd, and surprisingly appeared to improve BC too. Doing both made the biggest improvement to both group size and BC, but only marginally to the latter - but still well worth doing for the group size reduction at 600. Calculated BC improvement was in the order of .45 increased to a little under .5 over 200 yards.

I'm sorry but I don't get this. Every article, instruction manual and promo I've ready about meplat tools indicates that they worsen B.C. somewhat but overcome it with consistency of bullet tip, thus reducing group size. Did you mean BC consistency or actual BC increase. It just doesn't add up.
 
Doug,

your understanding of the issue is also mine, and ties up with what Bryan Litz says in his book Applied Ballistics for Long-Range Shooting. Larger meplat diameter equals lower BC. Bryan says that pointing increases BC by 3-8% depending on the mixture of calibre and original meplat diameter. So trimming alone should improve ballistic consistency, but at the cost of a small increase in actual BC by increasing average meplat diameter.

However, that's not what this test found according the authors - they report a small apparent BC improvement from trimming alone. Don't ask me how or why! I assume it's a statistical quirk - the sort of thing you get when the effects caused by the changes made are very small. (As we often see when reading reports of weight batched cases giving larger MV ES and SD values comapred to a mixed sample of the same cases that encompass a large weight spread, for instance.)
 

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