At risk of revisiting an old chestnut .....Is a 21" 270 likely to produce any more velocity than a currently owned 20" 7-08 that manages 2,800fps with 140s?

Just happen to have been offered a bargain, after the initial desire to snap up a bargain a little voice is telling me I am only going to get a very slightly faster, much louder, much heavier rifle which in the cold light of day doesn't seem such a bargain.

With reloads and equal pressure I wouldn't be surprised if the 7-08 wasn't a higher velocity in the short barrels.

Either way the difference wouldn't be enough to notice.

With my 18.5 inch SAKO barreled carbine I get over that velocity. A friend and I went to the range one day with my 7mm-08, my 7mm Mag SAKO, and his 7x64 SAKO and my chronograph. He took along his LEE portable hand press. Were were amazed how close his 7x64 came to my 7 Mag velocities. It was also an eye opener how the little 7mm-08 threw those 139 grain Hornadys.

There is little doubt that all those calibers mentioned and the 270 are good cartridges. I think another overlooked good cartridge is the 280 Remington. I think a better cartridge then the 7 Mag that died is the 7mm Sharpe & Hart.

I don't think there would be very much difference between the two comparisons.

quote:

Either way the difference wouldn't be enough to notice.

I can't say for sure because each rifle is different, but my 22" BDL .270 clocks an honest 3150 fps with 60 grains of AA 3100 behind a Speer 130 gr. GS... So I would expect more velocity from the .270.

no meaningful difference in the field.

The ol' 308 vs 30-06 stuff again in a different shirt.

There is an ~18% difference in case capacities...all things being equal...like barrel length and pressure...the larger 270 case will always achieve a higher velocity, but at an attendant increase in powder amount. Anywhere from 100-200fs depending on all the various factors being equaled out as close as possible.

I never had a 270 but I've built several 280's and now all I have is 2 7-08's and a 7mmRM and a couple barrel blanks.

As far as velocity is concerned I could always equal and slightly surpass friends and aquaintances 270's with my 280's as long as they BOTH were loaded to similar pressures.

Sure used to upset a few folks when I chronoed them side by side...not only that their beloved 270 wasn't getting the advertised velocities but that my 280, which was supposed to be much slower, was waxing their tails. Those chrono's sure were de-lier's and eye openers with some of my earlier supposedly "super wildcat", powder eating, hi-velo, barrel burning, bug-guns that weren't so hot after all.

I've also built several 284's and using specific reloading proceedures I could get velocites equal to 7mmRM factory ammo with long throated 284 barrels and seating the bullets out as far as I could. Of course, I could use the same reloading procedures with the 7mmRM and achieve 100-200fs over factory ammo.

It stands to reason that a larger capacity case can achieve higher velocities, but you have to go beyond the mundane "normal" reloading activities to really get that extra "pizzazz".

A better comparison I think is the 270-08 vs the 7mm-08, then all you have is the 0.007" difference in bullet diameter.

No matter how you cut it, each rifle is it's own separate entity and produces velocities that may be higher or lower than another one that was built on the same line just before or just after the one you might have.

It really make no difference to the game WHICH rifle you shoot. As long as you put the bullet in the right place you will have meat on the table.

I like my 7-08's, a 15" XP-100 and a SA 22" Ruger switch barrel...I also like my 7mmRM as I can shoot heavier bullets. At one time I had in the neighborhood of 30 7mm cal rifles, pistols and switch barrels, now I'm down to 5...??...WHAT HAPPENED? HAHAHAHAHAHA

Luck

The animals ain't gonna notice any difference.

Foobar, I would generally concur with everything you have said and of course ballistically you are correct in that the larger the case capacity the greater the velocity potential within acceptable pressures.

The only thing that upsets this in practice is when we start looking at shorter barrel lengths and comparing velocities of various cartridges.
In some cases with short barreled rifles the smaller shorter cartridge able to use faster burning powders efficiently e.g. the 7mm08, can produce high velocities than say the 270W which generally requires the slow burners to achieve their full potential.

With 18" - 20" barrels faster powders that produce their peak pressures quicker and burn within the short tubes in theory should give higher velocities to the lighter bullets we are talking of in the 7mm08 and 270W.

Not to say that the 270W may produce good results with a faster powder in the short barreled rifles but usually a reloader would be focussing on the known good results achieved with slow burners such as the 4831s etc, whereas the go to powder for the 7mm08 is Varget/4064.

Not long ago I was in an Academy, which is a Houston, Texas based sporting goods chain, looking at Stevens 200s that were on sale. This particular store had a 7mm-08 and a .270 available at the sale price. I asked about the one in front, and he said it was a 7mm-06. I asked him if it could be a 7mm-08 and he allowed as how it could be. I could see that the second gun was a long action so I asked what it was. He said it was a .270 Winchester. Then he began explaining to me that the 7mm-ought-”O”8 was a pretty small gun and that I would need to be very careful with it. I would have to be very careful with shot placement; anything less than a perfect shot would cause me to lose the animal. On the other hand, the .270 Winchester was powerful enough “for anything.” This was in the same store where another gun counter guy told a customer he could shoot .243 in his 6mm because the boresize was the same......

LWD

The variations between rifles would probably be greater than the velocity difference between the two in short barrels.

QL give the advantage to the 270 but by less than 50fps

Brass for the 270 is everywhere. Brass for the 7-08 is more hit and miss.

Once again, cops, GIs, guys standing behind gun counters, and people working in gun shops are not neccessarily experts.

If you could find 100 7-08 cases, how long would it be before you'd need to find some more?????

My father just purchased a 7-08 a couple of days ago, and was able to find brass on the internet easy enough, but its not the same in the gun stores in the seattle area.

quote:

Originally posted by winbag338:
My father just purchased a 7-08 a couple of days ago, and was able to find brass on the internet easy enough, but its not the same in the gun stores in the seattle area.

That's why you order stuff from Midwayusa or Grafs and son, plus a host of other places. Cheaper too.

My Speer reloading book lists a Rem 700 varmint model with a 24 inch barrel as its test bed for 7mm08 loads, and they achieved 3000+ FPS with their 130 grain bullets. Is not the 270 Win listed as getting 3100+ FPS with a 130 grain bullet .007 inches less in diameter?

quote:

Originally posted by ramrod340:
With reloads and equal pressure I wouldn't be surprised if the 7-08 wasn't a higher velocity in the short barrels.

Either way the difference wouldn't be enough to notice.

The 270 is the BIGGER ENGINE. Period.

Have had them both... the 7-08 will turn in around 2,800 (max) with a 140 from a 20" barrel... the 270 will run around 2,950 with a 140 from a 21" barrel.

quote:

Originally posted by Brad:

quote:

Originally posted by ramrod340:
With reloads and equal pressure I wouldn't be surprised if the 7-08 wasn't a higher velocity in the short barrels.

Either way the difference wouldn't be enough to notice.

The 270 is the BIGGER ENGINE. Period.

Have had them both... the 7-08 will turn in around 2,800 (max) with a 140 from a 20" barrel... the 270 will run around 2,950 with a 140 from a 21" barrel.

The 270 is in the 30-06 family of cartridges, while the 7-08 is in the 308 WCF family.

Apples and oranges to me...pretty much like trying to compare the 30-06 with the 308

If I had to select just one...I'd choose the 7-08. Just like the 7's better than the 270.

My current three Mod. 70 Fwts, with 22" tubes all run 150NPs at 2900 using warm but safe loads of RE-22.

I have a Remmy 600 Mohawk action and sts Mtn. rifle tube-22" and am maybe going to built a 7-08 U/L rifle for when I get old, but, it will not match the .270Win. and I have had at least a dozen rifles so chambered since 1968, it's a goodie and very efficient.

I find my .280Rems about the same and love them both as my usual hunting choice.

quote:

Originally posted by Brad:

quote:

Originally posted by ramrod340:
With reloads and equal pressure I wouldn't be surprised if the 7-08 wasn't a higher velocity in the short barrels.

Either way the difference wouldn't be enough to notice.

The 270 is the BIGGER ENGINE. Period.

Have had them both... the 7-08 will turn in around 2,800 (max) with a 140 from a 20" barrel... the 270 will run around 2,950 with a 140 from a 21" barrel.

BS ... my 7-08 will push a 140 grain Partition at 2936 fps.

My 7mm08 with a 21.5 inch barrel gets 2915 with 140 MRX's and Varget powder.

Velocity or not as BOTH are likely to send you deaf very quickly! Especially the 270 in that barrel length! I'd avoid!

quote:

Originally posted by enfieldspares:
Velocity or not as BOTH are likely to send you deaf very quickly! Especially the 270 in that barrel length! I'd avoid!

earplugs

quote:

Originally posted by wasbeeman:
The animals ain't gonna notice any difference.

My thoughts exactly. It sounds to me like the OP has a 7mm-08, in which case having a 270W would be almost redundant. Not that a 270W is bad cartridge, not at all. In theory and on paper, the 270 will have a slight edge over the 7mm-08 (and let's be honest, a 270 will give more powder capacity, and slightly sleeker bullets); but my thought is that if you are in a situation (I'm thinking along the lines of long, open-country shots, maybe antelope hunting or stuff like that) where you would actually be benefited by those advantages over the 7mm-08, you might as well skip the 270W and go to something like a 25-06.

If on the other hand the OP doesn't have a 7mm-08 and is wanting a good deer gun, go for it; it is well known that a 270W is an extremely capable round.

This reminds me a little of the recent thread about 7mm-08 vs 308. I shoot a 7mm-08, my Dad shoots a 308, one of my brothers shoots a 270, and the other brother shoots a 30-06. And, at the end of the day, I'm quite confidant a well-placed shot from any of the above four will kill creatures up to elk quite dead. It's actually hard to go very far wrong, and thus it becomes a matter of personal preference.

I can't believe that someone actually said that 7-08 brass is harder to come by. 308 brass is everywhere and anybody that owns a reloading die can have all the brass they need.

These discussions are relatively meaningless to the critters that get shot, but they do give you some viewpoints to look at if you are considering the calibers being discussed.

quote:

Originally posted by graybird:

quote:

Originally posted by Brad:

quote:

Originally posted by ramrod340:
With reloads and equal pressure I wouldn't be surprised if the 7-08 wasn't a higher velocity in the short barrels.

Either way the difference wouldn't be enough to notice.

The 270 is the BIGGER ENGINE. Period.

Have had them both... the 7-08 will turn in around 2,800 (max) with a 140 from a 20" barrel... the 270 will run around 2,950 with a 140 from a 21" barrel.

BS ... my 7-08 will push a 140 grain Partition at 2936 fps.

You're pushing WAY too hard likely... or have a 26" bbl.

quote:

Originally posted by Brad:

quote:

Originally posted by graybird:

quote:

Originally posted by Brad:

quote:

Originally posted by ramrod340:
With reloads and equal pressure I wouldn't be surprised if the 7-08 wasn't a higher velocity in the short barrels.

Either way the difference wouldn't be enough to notice.

The 270 is the BIGGER ENGINE. Period.

Have had them both... the 7-08 will turn in around 2,800 (max) with a 140 from a 20" barrel... the 270 will run around 2,950 with a 140 from a 21" barrel.

BS ... my 7-08 will push a 140 grain Partition at 2936 fps.

You're pushing WAY too hard likely... or have a 26" bbl.

That may not be necessarily true. Here a just one load from Hodgdon's online data:

140 GR. SFT SP IMR IMR 4007 SSC .284" 2.750" 41.0 2533 36,300 CUP 46.0 2847 49,600 CUP

That is realistically cost to the poster's velocity. Bare in mind that barrels are different and bullets are different brands, all which can make the velocity higher or lower. Also consider that the pressure is give in CUP which appears lower then PSI. That CUP listed in the max load can go higher as the CUP top max is in around 50 to 52K.

I do think that 7mm-08 can do that velocity.

Well, never having owned a metric anything, I can't directly comment on your 7-08. I can however comment on a .270. I run 150 Partitions in my pre-64 - 22" barrel, I assume. And I get 2930 fps on the chrono using a near max. charge of Rldr-22.
Guess the choice is yours.
Bear in Fairbanks

The real advantage the 7mm-08 has in this case, being they are so close to one another, is that 7mm-08 is on a medium size action and the rifle will be lighter and overall length shorter with equal barrel lengths.

My, my. What a can of worms. Actualy if you compare bullets from a BC perspective as opposed to grains I think that the 260 is actualy more comparable to the 270 than the 7-08. I consider the 260 to be the 308 version of the 270 and looking @ bullets from a sd point of view the numbers agree. The thing I personally like about both of the 08 versions though is that they dont have the notorious 270 muzzle blast. Kill critters just as dead though.

What you say is true, Eagle27, all powders have a specific burn rate, some powders are more efficient than others, some have more muscle so to speak, single vs double based powders and all that jazz. But..you should optimize whatever load in whatever case you use. If you don't you're basically wasting components even though you might still be getting your table fare.

It still boils down to case capacity...you can get just as much efficiency out of the larger case as you can out of the smaller case by using the correct powder and in doing so makes a non issue out the argument...the 270 case still has 15-20% more case capacity depending...so you can get a velocity pecentage of the 15-20% more case capacity, all things being equal which translates to whatever velocity you want to calculate or happen to measure...a quick look at a few manuals or an acutal test should give you enough data...it may or may not be enough to float YOUR boat but it IS higher....how much depends on a lot of factors and as always everyone is coming from different directions with different data that may or may not be nothing but a figment of the chrono's imagination...my Beta chrony is optimistic by ~100 fs over the Oehler 33, or maybe the 33 is just pessimistic...it doesn't matter as long as I average the information.

The only way to actually test this is to compare a 270-08 and a 270 in the SAME barrel cut to 20" or whatever lenght you want...shoot a test group optimized for a specific bullet, whatever you want, in the 270-08, then rechamber to 270W and shoot another set with an optimized load with the same bullet. THIS will tell you the difference in velocity of what the two case capacities actually is....not a bunch of horse patoot and whizzing in the air, guestimates from what a manual says or reading tea leaves.

This same test has been done many times in the past...I have tested MY different 308(I have 3 - 308 barrels) and 30-06 barrels on a Savage switch barrel LA receiver with barrel lengths of 20" in the 308 and 22" in the 30-06...AND...a 24" 300 WM...the 308 has a heavy varminting barrel and the 30-06 and 300 WM are both about #3 contours...I used a 180 gr Hornady SP bullet and worked up the highest velocity and most accurate load for each barrel...and chrono'ed them over a Beta Chrony and an Oehler 33 setup one in front of the other.

Ibendooingthis a long time so I know how it's done and I couldn't get the the 308 velocity to match the '06 anyway, anyhow...not with the 180 gr bullet, not with the 165 gr bullet and not with a 150 gr bullet, but I could get a 165 gr bullet in a 308 to match and surpass a little bit a 180 gr bullet in the '06...not withstanding the 2" barrel difference...easy enough.

Come on guys...when you're talking over 2800 fs with a 140 gr bullet in the 7-08 you are at the top end of the pressure and velocity spectrum...the case is packed to the gills and possibly compressed...don't try to sh** and old sh**ter...I been sh** before...and I have TWO 7-08's and have built several 280 and 284 rifles AND pistols, so I KNOW what I can get out of a rifle. I never had a 270 but I have chrono'ed and worked up loads for enough friends to know what THAT rifle is capable of...when kept within SAAMI specs.

I don't claim to be an expert or some kind of GURU knows all, sees all, but I have my own 150 and 1200 yd ranges, a lathe/mill and I can and do all kinds of playing around just to see what happens. If it wasn't a**hole deep to a tall giraff in snow right now with below zero temps I would make up a test barrel, do some tests and post the data...just as I stated above...testing apples and apples, only the difference between a 7-08 case and a 270 case with optimized loads in the SAME 20" barrel.

I think this would put to rest some of the "stuff", but then again a whole lot may not understand the significance.

Just enjoy your toy and don't try to make it something it isn't...actually OR online.

Just as a 280 ain't never gonna beat a 7mmRM bullet weight for bullet weight with the same difference in case capacity as the 7-08/270-280, the 7-08 ain't never gonna beat a 270/280 same bullet weight for same bullet weight...the laws of physics and thernodynamics won't allow it because whatever you do to the smaller case to increase velocity, you can do the the larger case and get an attendant velocity increase.

Luck

Here we go again!!! ***270*** is a caliber not a cartridge. Are you talking about a 270/378 Weatherby or a 270Ren(22 Hornet necked to .277") or something inbetween? PS: Jeffeosso- you never posted that load data for the 30 and 35 guns.

quote:

Originally posted by 1894mk2:
At risk of revisiting an old chestnut .....Is a 21" 270 likely to produce any more velocity than a currently owned 20" 7-08 that manages 2,800fps with 140s?

Just happen to have been offered a bargain, after the initial desire to snap up a bargain a little voice is telling me I am only going to get a very slightly faster, much louder, much heavier rifle which in the cold light of day doesn't seem such a bargain.

The 'book' velocity difference is about 200fps in favour of the 270 with 24" barrels. Chopping 4" off for the 7 and 3" off for the 270 is not going to reduce that difference. How much 200fps matters depends on the specifics, but I expect not much at 'typical' ranges.

Phew, Foobar by the time I read through your last post my head was spinning like your old lathe/mill.

You are on the button though in everything you have said. I suppose the original question has been answered but overall both the 7mm08 and 270 and other similar cartridges all can do much the same, some a little better than others and manufacturing variations in rifles can influence results as much as anything.

Now out of all this I think the best statement was by SmokinJ:

quote:

I think a better cartridge then the 7 Mag that died is the 7mm Sharpe & Hart.

This really made my day as I have always 'defended' the 7x61 S&H having owned and extensively used two of them. Lyman and Sierra always praised the efficiency of this cartridge while Hornady in particular seem to skew their comments to imply the 7x61 was a little inferior to the other 7mm Magnums even though their published reloading data indicated it was as good as, if not better, in some loadings even with them using a 26" barreled Universal Receiver for testing the 7mmRM and a 26" barreled Weatherby rifle for the 7mmWM while 'handicapping' the 7x61 to a 24" barreled rifle whereas most of the Schultz and Larsens chambered for this cartridge when it made its name, were 26" barreled).

Factory ammo in my Schultz & Larsen M60 and M65 chronographed within reach of their factory spec of 3100fps and I loaded the sleek 160gr Sierras BTs to an honest 3000fps so there were no flies on this cartridge.

Hornady's approach puzzled me to the point of writing to them many years ago to get their take on it. The letter I received from Steve Hornady in reply did not really explain why they comment as they do on the 7x61 S&H cartridge in their reloading manuals but he finished by saying his father had actually taken a huge record book moose with a 7x61 S&H so did in fact have an affinity for the cartridge.

quote:

Originally posted by Fat_Albert:
Here we go again!!! ***270*** is a caliber not a cartridge. Are you talking about a 270/378 Weatherby or a 270Ren(22 Hornet necked to .277") or something inbetween?

Do you bad boys hear that! From now on I don't want you saying, "I shot him with my .270". It should be "I shot him with my .270 Winchester Center Fire." so as to remove all doubts as to what you were using. (fyi, I've never heard of a 270Ren or a .270/.378Wea. But then, I don't get out much.)

Negative!!!, Fat Albert....the 270 WCF is BOTH a cartridge...the 270 Winchester Center Fire brought out in 1925 by Winchester AND a cartridge that uses a 0.277 caliber bullet...just as MANY cartridges have the caliber and/or the case as part of the nomenclature.

When most people say "two seventy", others that have a shooting background will know the speaker is talking about the 270 Win...

Just like saying 308 or 7.62x51 or 7.62 Nato or M14...223 for 5.56 or AR15/M16 etc...I know exactly what you mean and that it is both the caliber and the specific cartridge...if I/you want to mean something else, the specific naming convention is used..."my Swede" is understood to mean the 6.5x55 cartridge unless I/you specify another specific meaning for "Swede"...M98 is a Mauser...etc...it is ingrained almost, at least in the older crowd...maybe not so much in todays younger world as so many other .277 cals have come along.

"A rose by anyother name smells just as sweet"...hey

One bit more on case volume...the differences between the 250 Sav/250 AI, 257 R/257 R AI and the 25-06. There is about 8% difference between each standard and AI case, and about the same % difference between the 3 different case volumes...ROUGHLY speaking, don't go nit picking here.

AND...There is a fairly large difference in velocitiess in the separate standard case and each AI version...and the smaller AI case gets pretty close in velocities to the standard case of the next larger case size and the 257 AI will equal or surpass the 25-06 velocities.

One of the major bullet makers at one time used the 257 AI to test their 25 cal bullets and someone slipped and published the data. They went back and squashed those higher velocities in the next published manual...and they had a very hard time explaining WHY the 257 AI out did the vaunted 25-06 at it's own game and WHY they couldn't get equal or higher velocities out of the larger case at SAAMI spec pressures.

Don't believe me...take a look at some of the older reloading manuals...it's out there.

This goes to the efficiency of the case and powders...the sharper, less tapered case seemingly is the answer and TODAY we see that understanding in the newer offerings like the WSM/WSSM/RUM cases, the 308 family...less taper, sharper shoulders and much better powder...AND the fact that the 257 AI is a wildcat that gets loaded to higher than SAAMI specs many times.

Some of the problems are newer reloaders just use what they find online or in reloading books and most people don't want to do the heavy leg work, while the old timers had to do all the work by hand...and a large percentage of the average hunting people nowadays just want something quick...they don't have the time or the inclination to experiment. You miss out on all the sutle nuances of the reloading/shooting sport the don't get learned or fully understood unless you work at it.

If you take the time to do the little, boring stuff...measuring, weighing, trying one then another powder, changing primers and seating depths, prepping cases etc...you would be surprized just what you will learn, and how well your rifle will perform...and if you're more interested in being right, than being right, then you've missed out on all the interesting information so many others have presented.

I watched a shooter work with the 270 Ren on steel many years ago, it was a trip looking at that case and what it did to the Rams. My buddy from college days came across a 270/378 W in a trade. Damed thing had a 22" bbl, shot fire 30 yds downrange, was totally blinding and amazing to shoot at night and we never could get a decent group, more like a pattern. The stock was beautiful so he had a standard 7mm Weatherby barrel installed and never looked back.

Luck

wasbeeman & Foobar can you two send me some load data for a 30cal and a 35cal? I sure you know the ones that I am talking about.

Sorry FA, the world just doesn't work to suit you does it. Were there a myriad of different proprietary .270 calibre chamberings, one could be expected to say .270WCF. But, except for a few, little known exotic chamberings, there isn't. So if someone sez I have a .270, it's understood that he has a .270WCF not a .277Mousephucker. Same deal with a .308 and a .280.
Life is only as hard as you make it.

quote:

Originally posted by Davis Goertzen:

quote:

Originally posted by wasbeeman:
The animals ain't gonna notice any difference.

My thoughts exactly. It sounds to me like the OP has a 7mm-08, in which case having a 270W would be almost redundant. Not that a 270W is bad cartridge, not at all. In theory and on paper, the 270 will have a slight edge over the 7mm-08 (and let's be honest, a 270 will give more powder capacity, and slightly sleeker bullets); but my thought is that if you are in a situation (I'm thinking along the lines of long, open-country shots, maybe antelope hunting or stuff like that) where you would actually be benefited by those advantages over the 7mm-08, you might as well skip the 270W and go to something like a 25-06.

If on the other hand the OP doesn't have a 7mm-08 and is wanting a good deer gun, go for it; it is well known that a 270W is an extremely capable round.

This reminds me a little of the recent thread about 7mm-08 vs 308. I shoot a 7mm-08, my Dad shoots a 308, one of my brothers shoots a 270, and the other brother shoots a 30-06. And, at the end of the day, I'm quite confidant a well-placed shot from any of the above four will kill creatures up to elk quite dead. It's actually hard to go very far wrong, and thus it becomes a matter of personal preference.

My wife and I needed to make this choice last year. She decided on a 270 Win.

For pronghorn sized game and Calif deer she shoots a 110 TTSX Barnes at 3450 fps in a 22.4" barrel. Honest, sub-MOA groups. For larger sized animals she has the Barnes 130 TSX (ironically with a better BC than the TTSX) at 3100 fps and 1/2" groups. If more testing confirms a measurable improvement in accuracy for the 130 grain bullet, she may switch to that for everything "270-sized" next year.

The 7-08 is a great calibre and she wouldn't have minded it instead of the 270 Win. However, the 7-08 can't match the above stats. As some have said on this thread, the 270 Win is a bigger engine. And I doubt that the 6.8mm versus 7.0 mm bore difference means anything.

Incidentally, her rifle was a Tikka T-3 stainless. Very light, 7.3 lb with scope. We put a limsaver recoil pad on it and she says that it shoots quite comfortably. But she only says that a similar lightweight 338 WM 'jumps a little' when shooting it. Good girl.

quote:

Originally posted by deadkenny:

The 'book' velocity difference is about 200fps in favour of the 270 with 24" barrels. Chopping 4" off for the 7 and 3" off for the 270 is not going to reduce that difference. How much 200fps matters depends on the specifics, but I expect not much at 'typical' ranges.

FWIW I agree. The extra 200fps could be less if it's a 'slow' barrel isn't worth the money, extra weight, extra length and worse trigger so I have passed up the 'bargain'.