6.5 or 7XC

[Guest]

How rude of me! "Piss off and leave" isn't my normal venue, so with sheet-rocking awaiting me, I believe this morning I'll have another cup of java and see if I might stir it up a bit more. This is a public forum. (wish I knew how to use all those BOLD and highlighter deals for emphasis, way cool)
Few years ago on the evening prior to the begining of the Nationals,a few folks were gathered about a picnic table shooting the breeze. I,,,, an aspiring AA shooter was going on and on expounding the virtues of my 7X250 wildcat super silhouette cartridge,,,when out of the blue from across the table dead-eyed serious and without cracking a smile a gent replies: "None of the top shooters are shooting wildcats!". Whoa! How rude. Does he not realize the depth of study and research I've put into this? Who does he think he is?
Contrary to how it appears in the earlier posts, we are not complete strangers, as about a year ago this month as a matter of fact. I responded to one of your inquiries over on BRC. Your request? How fast will a 180 go in a 7BR? I pm'd you my load data, data I might add, that was not obtained from a few shots over the chrono in winter but over several range sessions, dozens of matchs and conferred on with couple of other shooters with much more experience that I. (one of em does it for a living). A few weeks later a gent from down under was again asking the question on BRC of the viability of the 7BR in Silhouette: http://www.benchrest.com/forums/showthr ... Silhouette Page two of the thread is especially interesting as two of the responders I know personnally as outstanding shooters and competitors, nailed down exactly the paramenters I had sent you earlier. "Better than average results" yep! 200+ fps more than some of the best minds in the sport!! Awesome! I'm not joking, I've dug primer shards out of my cheek from standing beside my wife's rifle during practice, It's not loaded to anywhere near the kahunas of the loads you're speaking of. These little cases can go from waaay cool to psychotic in a NewYork minute when loaded to the highest presure levels
At the most there'll be 6-8 or so 7BR etcs at the nationals (or have been for the last few years) so over 90% of the competitors haven't bought into it either. If you think I'm just an old white haired stick in the mud refusing to see the future may I add that of those 6-8 7BRs at the last two nationals, I personnally entered two of them. This year the little case cost me significant targets at Phoenix and at prior matchs.(not the direction I felt I wanted to go, and ram knockdown was NOT the factor) Depending on your needs and your dedication, discipline in loading etc. the 7BR can be a formidable competitor. I call it majoring in the minors, case design within reasonable parameters has minimal influence on final score. All cartidges capable of toppling a 50# target 1/3 of a mile away with any regularity are going to recoil to some degree. That's what makes the game special!!
Remember the gent across the table? Three days later I, with my ego bruised stood in the 11th or 12th spot in AA. He on the other hand came forward to accept the award as that years national champion. Had I "heard" what he was saying then I might have saved myself years of learning and mucho $$$$'s. Seems I had superior balistics, terminal performance, higher BC's, and memorized wind drift tables. He had a case 2/3's full of powder and a performance worked out through hours, weeks, months and years of training. The scoreboard showed the differance.
And why all this from me, a non-prolific poster? Why my concerns over one who wishes to play in the freeway? Because: "If my results are any indication of normal then I would say that a bigger case is not necessary" The allure is undeniable. The "freelunch" gets us all. Nobody is dumb enough to run out and try to duplicate this!! Right? Well,,, let me introduce myself. Not too many years ago I was hooked on this HP game from an article in the Sierra load manual. As the closest range I was to find was 230 miles away, and not wanting to arrive "uneducated" I sought knowledge. I found it from a knowledgable sort on the internet. Turns out the ol boys at the range didn't have any of my "knowledge"! Also revealed over subsequent posts (IN MY CASE) my coach had never actually been to a match (hell of a writer though). If a beginer is reading this and has suffered through to this point, take a word of advice. Buy nothing! contact the match director a few weeks prior to your chosen match and tell him straight up----want to play----have??? ---know nothing----show me!!! Works much better, I promise.
So,,, we on the same page yet? Still "pissed" at me? They say it's good cardio. Look me up at Ridgway, we'll do dinner or something after it's over. High score eats free! What do you say?
Look on the bright side. Spring is near, I've rifles to finish assembling, several needing paint, house to finish. etc, etc. All of which could mean you're not having to hear from me for months!!! Be Happy!!
Carroll

[Troy G]

Carroll,

I am not mad at you. Like I said I don't know you and I am not going to debate or argue with you on a public forum. I will safely shoot my case, you shoot yours, and we can both have fun doing it.

[dwl]

TroyG;

You won't mind if I drag this back to the original subject matter will you? I tried looking around for case dimensions for various cases between 7 Br and 308 just to compare volumes.

Two problems, one I could only find exterior dimensions for some cases and two, volumes ESTIMATED from exterior dimensions don't show much difference between the 308 derived and IHMSA cases. I have illegible metric dimensions for the 6.5X47 Lapua but nothing I can find for the 6 XC.

Would you happen to know a site where I can get volume or dimensional information on various 7mm silhouette candidates?

dwl

[Troy G]

DWL,

The case capacity for 3rd generation 6XC brass from Superior Shooting has been listed as low as 47 and as high as 49 grains which is supposed to be about 7-8 grains less than a .243 Win case. Other cases are the 6x47 Swiss Match which can be bought from Neal Johnson Gunsmithing as once fired brass. Case capacity is very similar to the 6XC. The new Lapua 6.5x47 is supposed to be 47 grains. I have no idea what the case capacity of the new Norma 6XC is going to be. From memory I think the case capacity of a .22/.250 case is around 42-43 grains, improved it would be pretty close to the above cases.

Check out the following links as well. 6mmbr.com is a good sight for the little cases.

http://www.6mmbr.com/BlogNov2005.html

http://www.6mmbr.com/6XC.html

http://www.6mmbr.com/albums/album_image ... 340387.htm

http://www.6mmbr.com/6BRImproved01.html

http://www.6mmbr.com/cartridgediagrams.html

[CB]

Seems once again my big mouth and opinionated nature have conspired to put me in an embarrassing situation. My apologies to the board and to Troy especially for my lack of consideration and insensitivity in my earlier posts.
I went out to the shop and rounded up all the brass I could find within the range of the request and hope yall will except this as partial penance for my mouthyness in posting.
All measurements are for comparisons only, water filled to base of neck, eyeballed as best I could. There was as much as 1-2grs differance between same cases in same batch of 7BR Rem brass so take it for what it's worth. Through in couple of extra just for comparisons.

.223LC brass 30.2grs.
7BRLapua 35.8 (shoulders blown out .015, match reamer)
7BR Rem 34.0 (same as above but .312nk saami reamer)
7BR Rem 35.0 (same as above differant piece of brass)
7X250 Win 43.3 (22-250 brass fired in chamber made by holding back
7-08 reamer ? thousanths, I forget)
7IHMSA 43.6 (from 300Sav brass)
7IHMSA 43.7 (from 22-250 Rem brass)
7IHMSA 46.4 (from 22-250 Win brass, shoulder blown out app .040)
7-08 48.3 (Lapua .308 nk dn)
7-08Rem 48.9
7-08Win 50.6
I have not personally seen a piece of the 6.5X47 Lapua brass but from what I was told from someone who has it is not a great stretch to assume it will become common in our game in the years to come. Capacity of about the IHMSA without the hassles of case forming should make it quite popular.
Once again perdome', my apologies for my improprieties.
Carroll

[dwl]

TroyG and CB;

Thank you for the information and the effort. It will give me something to ponder while the wife watches Desperate B:+ch@$ on TV.

CB;

Peccata tui dimittum.

dwl

[dwl]

Gentlemen;

I've chased around gathering data and did some minor pencil-whipping and I come up the the rather mundane discovery that compared to the 7-08 the 7 IHMSA has apx 10% less capacity, the proposed 7X - 13% less and the 7 BR 27% less.

While I can certainly see that a 27% reduction is significanct, is a 10% reduction significant? Is the 7-08 really running at 66% loading volume and therefore the 7X would run at 80% (i.e. similar load in a smaller case)?

dwl

[CB]

In a word, yes, it is. Sometimes. Question really becomes, is it significant enough for you to invest the time and labor to try it.

As a general rule, (a look at load manuals "Nosler" for one, that list load densities) you will likely start to notice that the .308 case (and a lot of others for that matter) will have a number of "most accurate loads" listed in the 78%-85% of fill volumne. One of the old test loads for the .308 40X from the custom shop was with IMR 3031 at much less than that. (not a long range load but super accurate at 100yds). As a result 37-38grs. of RL-15, Varget, IMR 4064 and other med burn powders will generally be in that round-up, with 150-168gr bullets in a 7mm. Shrink the case 10% to the IHMSA size and you're now getting the same velocities as the 7-08 is above but with app. 35grs+or- of same powders. The IMSHA is a much more ideal volumn for bullet size resulting in a more efficient use of powder than the 7-08 (max velocities aren't what we're after, and usually aren't the most accurate anyway). Drop it to a 7BR, well I'll not go into that again, suffice to say you're straining it to get anywhere near the above, hence the interest in high BC bullets to overcome the lack of velocity, which opens another pandoras's box of problems.
The reality of the matter is, and always has been, K.I.S.S.!! reloading, wildcatting, case forming, and bench racing is an awesome hobby that has entertained myself and friends and now us for many years. Don't allow it to become confused with an old game called HP Silhouette. It's difficult enough as it is. You're starting to question the right questions, be careful, this can be a long painful adiction to overcome. Some of us have resigned ourselves to never finding a cure.,,, Ah!!! the smell of varget on the damp morning air!!!
Dang, did I do it again?
Carroll

[Jerry G]

Keep in mind it is momentum that knocks rams over, not energy. A slow heavy bullet works better than a fast light bullet.

[DanDeMan]

Guys,

Been reading some of the old posts. This one was interesting to say the least. And, YES, momentum is a much better predictor of ram knock-down than energy; a terrible and inaccurate metric for ram performance. And, after years of testing; bullet construction is also very important. As an example, back in FLA, circa 1980, I used a 7TCU in HP Pistol Silhouette and got laughed at big time as most of the guys were shooting 7mm IMSA's, 7-08's or the 30-cal varieties. I never rang a ram and had those old boys scratching their heads when they rang one and I didn't. What was the difference? Bullet construction. The 162 grain Nosler Bevel Base bullets in 7mm were the toughest bullets around back then. Bullets were tested on a "bullet smasher" to determine which were the toughest. So, the moral of the story, as I've said for years, "Ya gotta shoot the high BC bullets to improve the ratio of the ram performance to felt recoil and they gotta be tough."

And, finally; there is no need to shoot the 175 to 180 grain 7mm's faster than 2,400 fps. All you will accomplish is collecting more recoil and possibly less ram knock-down performance. Faster terminal velocity means less bullet dwell-time, not necessarily more knock-down. Ideally we want our ram bullets to arrive with enough velocity to completely blow-up on the ram, but not any more velocity. Optimum terminal velocity will drive down felt recoil and increase bullet dwell-time. There are probably a few posters or lurkers on this site that have seen how devastating a 180 JLK 7mm bullet is on rams when launched at only 2,325 fps with 31.0 grains of VarGet.

Cheers,

Dan Theodore

[dave imas]

Where the HELL have you been!?! And I wish you would come up!!!!!!!

[DanDeMan]

Where the HELL have you been!?! And I wish you would come up!!!!!!!

Yo Mensch,

I've been in a large cloud of black powder smoke and all "wrapped-up" with barrel and reamer design, cartridge design, load developemnt, bullet design, ad infinitum, ad nauseam for paper-patched bullets used in long-range shooting matches. It's just one thing after another; will it ever stop???

I expect Team California to do well up at The Cup. I'm guessing the usual reprobates will be hanging out at Maison Imas, no? Make sure Jared's rifle is working properly this year

Cheers,

DanT

[nomad]

Who in Hell is Dan Theodore?

[DanDeMan]

Who in Hell is Dan Theodore?

Now E,

Be nice or I'll tell your better half to kick your butt at The Cup with extra alacraty and affect.

D