RECOIL and THE BLOEMING CASE

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John T
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RECOIL and THE BLOEMING CASE

#1 Postby John T » Sun Dec 17, 2017 12:26 am

Hello FCWC Aspirants.

Under the topic, "Somchem S 365...", GSells asked; "What about 28 nosler, 7mm RUM, or 338 Lap Mag- 7mm, 300 RUM!!" to which Rod Davies replied;

"Too much recoil, too much barrel heating, not as accurate as regular "magnums". Short barrel life and not staying in tune for long enough. They might be OK for very short strings, but certainly not
for 15 - 20 strings." (He could have added that the grey mist you see in your scope is not a cataract, it is your bullet disintegrating.)

You need to make Rod's message your mantra.

RECOIL IS CUMULATIVE.

Recoil tolerance may be up for bragging rights in the tough-man's corner of the bar, but you won't find any champions there.

The opening shot.

Regards,
John Tracey.

GSells
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Re: RECOIL and THE BLOEMING CASE

#2 Postby GSells » Sun Dec 17, 2017 8:42 pm

John T wrote:Hello FCWC Aspirants.

Under the topic, "Somchem S 365...", GSells asked; "What about 28 nosler, 7mm RUM, or 338 Lap Mag- 7mm, 300 RUM!!" to which Rod Davies replied;

"Too much recoil, too much barrel heating, not as accurate as regular "magnums". Short barrel life and not staying in tune for long enough. They might be OK for very short strings, but certainly not
for 15 - 20 strings." (He could have added that the grey mist you see in your scope is not a cataract, it is your bullet disintegrating.)

You need to make Rod's message your mantra.

RECOIL IS CUMULATIVE.

Recoil tolerance may be up for bragging rights in the tough-man's corner of the bar, but you won't find any champions there.

The opening shot.

Regards,
John Tracey.

Hi John , I believe an accurate Saum or hopefully 280 Ai maybe more appropriate! Although I believe coaches and captains won’t take a risk on the 280 ai unless it can be proven over the next few years ?
The saum is already proven and has the runs on the board . Also the 7-300 wsm May make a comeback?
However Accuracy always trumps speed and whether a cal can last the whole Comp from Development to the last shot and holding its tune will be paramount I guess??

I’m looking forward after NZ trying to prove the 280 ai and if I can’t , I will be switching to a saum !
Also a lot can happen in 4 years with burn out a real possibility for shooters playing at the top !!??

Failing all of that , can I take my 338 edge ?? :lol:

John T
Posts: 152
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Location: Brisbane

Re: RECOIL and THE BLOEMING CASE

#3 Postby John T » Mon Dec 18, 2017 12:11 am

GS, there has been no greater champion of the 280 AI than Matt Paroz. He now shoots the 7 RSAUM. Do not waste another dollar on the 280 AI, it is as passé as the 7x57 AI.

Recoil; tolerance; awareness; distraction.

If recoil causes distraction, fine accuracy is lost.

Tolerance of all things; such as pain, discomfort, alcohol, irritation, criticism, abuse; is subjective.

No one can tell another his or her level of tolerance. Not infrequently, the individual is incapable of accurate self-assessment of a tolerance.

In the case of recoil; "This load is a bit heavy, but I can handle it", is self-delusional.

Let's say you are developing a 300-7WSM. Your previous was a 284 Shehane. Recoil was noticeably greater early on, but you have acclimatised and are no longer conscious of the heavier recoil.

You have a node and are increasing loads, searching for the next. You think you've found it. You load two batches of 2+10, each of the lower and higher loads. You know that recoil is cumulative. To off-set any effect, you shoot the heavier load first.

Everything goes well, except that toward the end of the first string you become aware of a change. You feel some recoil, not much, but it was not evident before. No such awareness occurs during the second, lighter, string.

Both groups are more than acceptable, with nothing between them. So you opt for the heavier load. 80 fps must be worth something (you think).

Over the next weeks/months, "late recoil" becomes the norm, as does its distraction. It is there, but no longer recognised.

The quality of you groups are not what they once were, but you don't know why.

You are overloaded.

The theoretical BC advantage of the extra 80fps will never overcome the loss of accuracy caused by additional recoil.

Do not launch into a new cartridge until you have experienced it. If you do not acclimatise, the case is not for you.

Recoil awareness = distraction = inaccuracy.

Recoil is insidious. It needs to be tolerable and controllable by each individual.

Regards,
John Tracey.
18.12.17

Gyro
Posts: 349
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Location: New Zealand

Re: RECOIL and THE BLOEMING CASE

#4 Postby Gyro » Mon Dec 18, 2017 12:40 am

Yes John T it's a no brainer in my book too. I shot a 308 FTR rifle free recoil with heavy bullets and believe my "state of mind" benefitted hugely from having a recoil absorbing butt plate as well as some special padding in a cut-down wetsuit jacket I used to wear. BTW a shooter using a heavy recoiling F Open rifle could do similar easily.

You're toast once ya become conscious of and timid of recoil.

Let alone the increased "gun upset" and all the side effects that goes with that.

John T
Posts: 152
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Location: Brisbane

Re: RECOIL and THE BLOEMING CASE

#5 Postby John T » Wed Dec 20, 2017 11:37 pm

The Case for Bloemfontain.

The 7RSAUM could be loaded to drive a 183SMK at about 3000 fps. Recoil would be beyond "tolerable" for most shooters. I cannot comment on the accuracy of such heavy loads for this case.

The most common larger case is the 7WSM/300-7WSM, with about 12% more capacity. It has the advantage of producing a wider range of nodes at higher velocities with lower spike pressures. How this translates into "tolerable recoil" and fine accuracy, I do not know. Of those who have travelled the WSM trail, Rod Davies is the best qualified to comment.

Note that the WSM family is not highly regarded for its fine accuracy. Rod may have something to say about the accuracy of light to moderate loads in this case.

In 2009 at Bisley, Great Britain used the 270-7WSM (a slightly smaller case). The opposition of 284WIN's and 6.5-284Lapua's were literally blown away. Yet no country has used a WSM at FCWC since.
Hail Rod! again. He will know who used what, where, when and with whom.

Does this mean the 7RSAUM is it? No. It is no more that the best currently available. It would be sensible to stick with it for now and develop it as your increasingly reliable partner. Even if you made the 183SMK your sole bullet of choice, there are more than enough makes of barrel and barrel configurations to occupy your time and credit card over the next two years or so.

Now to the real point of this topic. Should we anticipate new developments in long range precision shooting that will impact on FCWC and plan for them now?

Yes.

My prediction is that one or more major case manufacturer will produce a very wide-bodied, short case which could be available to Australian shooters by 2020.

These cases will have rims of about 0.580 and may be rebated from base diameters of about 0.600. They will be no longer than 2.000. (Think, a very short 338 Lapua with a long neck.)

Who can remember the last case design, in the USA, that was not a shortened, necked-down, blown-out, improved version of a cartridge from the families of Rigby, Jeffery, etc., of the days of the great white hunter? The 338 Lapua is a poor improvement on the 500 Jeffery. It was rejected by manufacturers in the US.

I believe that Hornady, innovative in design but dismissive of the need for the best quality, has provided the impetus for the next generation of ORIGINAL case designs. Look at their 6.5 Precision Rifle Cartridge. It has what is currently known as the standard magnum rim, 0.532. "Magnum" does not appear in its title. Because Hornady no longer regards this case size as a "magnum"?

There is nothing special about the 6.5 PRC , other than it is, simply, original. I see it as the first of simple, wider bodied, short cases with longer necks, that will dominate all rifle cartridges in the future. (BTW, the 6.5 PRC will be an excellent cartridge for short range F Class.)

A wide-body, short case for the bigger boys? Not achievable with what will soon become the standard case head of 0.532. The next up, historical, in rim size, is the 0.580. There are plenty of cases and plenty of rifles that have this rim size and bolt face.

The next case for use at the FCWC will have a rim of about 0.580. It will fit into a short action.

The Plan.
Acquire an action that will accommodates a bolt with a 0.580+ face (allow 12 months).
Build a rifle with your 580 action (allow 10 months).

GET YOUR 580 ACTION (bolt), AT LEAST.

Good night and good luck.
John Tracey.
20.12.17

bruce moulds
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Re: RECOIL and THE BLOEMING CASE

#6 Postby bruce moulds » Thu Dec 21, 2017 6:13 am

john,
one could be forgiven for thinking you are serious.
keep safe,
bruce.
"SUCH IS LIFE" Edward Kelly 11 nov 1880
http://youtu.be/YRaRCCZjdTM

John T
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Location: Brisbane

Re: RECOIL and THE BLOEMING CASE

#7 Postby John T » Sun Dec 24, 2017 1:08 am

Hello Velociters.

About 20 years ago, John Lazzeroni (a champion Velociter) introduced his very powerful hunting rifles which were complimented by very powerful cartridges designed by him.

An indication of the power of his cases and the strength of his receivers is the 8.59 Titan (.338). With less capacity, it delivers more muzzle energy than the 338-378 Weatherby Magnum and considerably more than the 338 Lapua Magnum.

There is also a family of short magnums. All of these cases have the same dimensions.
Rim 0.5811
Base 0.5799
Shoulder 0.5598
Case Head thickness 0.240
Powder Chamber 1.313
Shoulder to Mouth 0.497
OAL 2.050

This case has about 9% more capacity than the 7RSAUM, compared to the 7 and 300 WSM's, which are about 12% larger.

The efficiency of the powder chamber of the Lazzeroni short magnum is third behind the ultimate, the benchmark, the 6 PPC; and the 6 Dasher.

Matching the capacity of the Lazzeroni magnum "super chamber" to the best calibre, is a different task.

The cases of most interest to F Open shooters are the 7.21 TOMAHAWK (.284) and the 7.82 PATRIOT (.308).

The efficiency and capacity of the Tomahawk will propel the 183SMK at a comfortable 3050 and at 3100 without much push.

For me, I think the case may be a little over-bore, even by modern standards, for the .284. But then, very slow powders may balance that out.

I am, and will remain, a 7mm shooter. But it does seem that the 308 PATRIOT is a near perfect match. 215 Hybrid? I think so.

John's customers seem to agree - Patriot cases are not available. Expand the Tomahawk.

There is always the issue of recoil. I think Velociters can work it out with this case.

The big issue is cost. The catalogue price is USD3.50. Landed on your bench, AUD5.50?

Thing is, if you plan for the evolution, you have an option if the evolution is a bit late.

Regards,
John Tracey.
24.12.17

Gyro
Posts: 349
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Location: New Zealand

Re: RECOIL and THE BLOEMING CASE

#8 Postby Gyro » Sun Dec 24, 2017 4:22 am

What about some 'evolution' in the F Open rifle stock, especially if you're dealing with heavy recoil ?

Me thinks that may be a rich vein worth exploring !

I don't mean the 'American way' with a stunning paint job and multiple clear coats.

Just a design with function first ?

johnk
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Re: RECOIL and THE BLOEMING CASE

#9 Postby johnk » Sun Dec 24, 2017 7:07 am

All this isn't new.

When I was a lad, I can recall my father's shooting mates sitting round & yarning & more than occasionally they commented on case design - I think - with the phrase:

Short & thick does the trick; long & thin goes too far in.

BATattack
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Re: RECOIL and THE BLOEMING CASE

#10 Postby BATattack » Sun Dec 24, 2017 7:50 am

I think you will see the top 4 calibers will be 284, 284 "improved" (AI, KMR, shehane), 7saum and 300wsm with the last two making up the majority.

Recoil comes down to a lot of things but stock design and bag setup can make all the difference if done correctly.

bartman007
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Re: RECOIL and THE BLOEMING CASE

#11 Postby bartman007 » Sun Dec 24, 2017 9:13 am

Recoil comes down to a lot of things but stock design and bag setup can make all the difference if done correctly.


Too true, and not to overlook powder choice.

When i got my Saum going back around 2011, i tried 2217 2213 and 2209. Recoil was markedly different between the 3 powders! I settled on 2217 because of its gentle push, and its ability to be extremely accurate!

The only time that recoil annoyed me was after a day of shooting in the cold at Warracknabeal.

As another technique to minimise felt recoil, deciding to shoulder each shot has a great outcome too. But you should not make the mistake of shouldering every second shot as you'll experience elevation!

The key to doing well in SA will be to have a load that works in the climate and elevation and power limitations (if any).
###

Hangfire
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Location: South Oz.

Re: RECOIL and THE BLOEMING CASE

#12 Postby Hangfire » Sun Dec 24, 2017 8:03 pm

With the advent of new high BC 6.5 bullets like the 150g SMK I would not be surprised to see some 6.5 short magnums on the firing line.
Teams with deep pockets could turn up on the mound with a quiver of 6.5 barrels to burn. This type of cartridge would provide stellar performance in an extremely shootable low recoiling package.

John T
Posts: 152
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Re: RECOIL and THE BLOEMING CASE

#13 Postby John T » Mon Dec 25, 2017 1:00 am

Hangfire.

I don't want to discourage you, but the mv of a 150, 6.5 out of this case could well exceed 3300fps. Parker Ackley was of the view that "the law of diminishing returns starts to be felt if we go much above 3200 f.s.".

Can I suggest that you would need to buy 3 barrels at a time, one for load development, one for practice and PM's (500 rounds) and one for Queens' (500). You would certainly need two, maybe three shot-in barrels to take to a FCWC.

Don't forget the dreaded "grey mist". What is the twist for these 150's, 7 or less?

Regards,
John T.
25.12.17

Hangfire
Posts: 118
Joined: Mon May 31, 2010 10:05 am
Location: South Oz.

Re: RECOIL and THE BLOEMING CASE

#14 Postby Hangfire » Mon Dec 25, 2017 6:40 am

John T wrote:Hangfire.

I don't want to discourage you, but the mv of a 150, 6.5 out of this case could well exceed 3300fps. Parker Ackley was of the view that "the law of diminishing returns starts to be felt if we go much above 3200 f.s.".

Can I suggest that you would need to buy 3 barrels at a time, one for load development, one for practice and PM's (500 rounds) and one for Queens' (500). You would certainly need two, maybe three shot-in barrels to take to a FCWC.

Don't forget the dreaded "grey mist". What is the twist for these 150's, 7 or less?

Regards,
John T.
25.12.17

Personally I could never consider this type of cartridge in this style of shooting purely based on economics but if by chance I was fortunate enough to run into some serious coin and $ were no option then I would jump on this quick as a flash.

To run one and be at the sharp end in this event you would need to buy a minimum of 4 barrels. One for load development and practice and 3 for the actual event. Then hope each one of the barrels is a shooter. Then switch them out between each range to conserve them during the shoot.

A 150g 6.5 doing around 3100fps would have the edge over a 230g .308 at 3000fps and a 183g 7mm at 2950-3000fps.

Recoil Energy for these bullets at these speeds with a 10kg rifle would be:
6.5: 8.8 Ft Lbs.
7mm: 10.66 Ft Lbs.
30 Cal: 14.71 Ft Lbs.

I have experienced multiple bullet failures with my 7mm SAUM when shooting them fairly hard out of 32” barrels. Since I have taken to shooting them out of 30” barrels I have not had one single instance and would feel confident the same would translate to the 150g 6.5.

I threw that cartridge in the mix as there are certain teams out there who haven’t had much of a fun time of it as of lately and desperate time call for desperate measures. They have the resources and backing to easily go down this path. If they do only time will tell.

For me the 7mm still is King of the Hill in terms for this game but I have a 7.5 twist 6.5 on order to try in my SLR, if that proves unable to drive the 150g at a speed to be competitive against a .284 then I will chop it and chamber it in SAUM as a once off.

Old Trev-39
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Re: RECOIL and THE BLOEMING CASE

#15 Postby Old Trev-39 » Mon Dec 25, 2017 7:26 pm

as an aside to this topic, are the 150 M/K available here yet. and where. My enquiries a month ago at 3 outlets advised that the Aust. importer had no plans of importing in the near future.
Cheers,
Trevor.


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