Learned something today.
At the range today I cronographed a couple loads for a guy. Later I noticed his young buddy had the same rifle. Camoed Savage 22-250s. They told me the only difference was one had a 24" barrel and one had a 26" barrel, It may have been22" and 24". The youngster with the lager barrel said with the same load his was OVER 200fps faster. To which I gave a little snicker.
Long and short of it I fired both rifles with the same ammo over the Oehler.The longer barrel was 225fps faster. Would not have beleaved it but it was real. What a surprise. roger

I can believe it since you are talking two different rifles. If you ran a 22/250 over your ohler then cut two inches from the muzzle and shot the same load through the cut off barrel I doubt it would shoot that much slower.

d

quote:

Originally posted by bartsche:
Learned something today.
At the range today I cronographed a couple loads for a guy. Later I noticed his young buddy had the same rifle. Camoed Savage 22-250s. They told me the only difference was one had a 24" barrel and one had a 26" barrel, It may have been22" and 24". The youngster with the lager barrel said with the same load his was OVER 200fps faster. To which I gave a little snicker.
Long and short of it I fired both rifles with the same ammo over the Oehler.The longer barrel was 225fps faster. Would not have beleaved it but it was real. What a surprise. roger

I had two Savage 243s with 22" barrels. One of them was always 125 - 150 fps faster with every load I tried.

Interesting indeed. I always felt that powder was the main issue (slower burn/longer barrel - Faster burn/shorter barrel) and that the higher velocity with a longer barrel was due to the higher velocity with the slow burn up the barrel?

Experiments have shown that the powder giving the best velocity in the long barrel also gives the best velocity in the shorter barrel. This might change comparing to pistol length barrels, but in the normal 16 to 26 inches, the best powder is the same regardless of length.

Bruce

Could it be the chamber demensions rather than the barrel length? Just asking.


ddj

Chambers, throats, was the load really the same, same lot of powder loaded by the same guy, cases FL sized in one and neck sized in the other, number of rounds the same though each barrel, 22 vs 26" barrels perhaps and a whole host of other variables. Most probable was the barrel lengths and the load was not actually "the same".

Only way to know is to repeat the test actually using the same ammunition.

Larry Gibson

[QUOTE]Originally posted by Larry Gibson:
Chambers, throats, was the load really the same, same lot of powder loaded by the same guy, cases FL sized in one and neck sized in the other, number of rounds the same though each barrel, 22 vs 26" barrels perhaps and a whole host of other variables. Most probable was the barrel lengths and the load was not actually "the same".
this was the same ammunition exactlly.The shorter barreled fired cases did appear to have seen somewhat greater pressure.But still a difference in velocity that would indicate an energy transfer equal to a 12% increase in powder mass is surprising to me.I know what I saw was not totally indicative to barrel length difference alone but taking all possible contributers in hand it surprises me. Over 200 fps. increase is large. roger

i load for 3 different 30-06 with the "same" load, 3 different makes of guns. all 22 ".. shot over chroney, from the fastest to the slowest was about 125 fps different

bartsche

Sorry you misunderstood, perhaps I wasn't clear enough. I wasn't questioning that you didn't see what you saw, just pointing out all the possible reasons it may have been and the "usual suspects". I've chronographed a lot over the years and found such anomolies do occur but they are rare. A difference of 125 fps as vines points out isn't too uncommon. However the 200 fps for 2 additional inches of barrel is quite a bit and I also would have snickered. Most likely it was the difference in chambers, barrel dimensions and the powder used (related to the time/pressure curve). Smoothness and/or fouling also play havoc. Again, I am in agreement with you....I just didn't come across that way I guess.

Larry Gibson

Larry, I don't believe that this issue is rare. As a matter of fact my best buddy and I have 2 Remington 700's in 223 Rem, 24" Heavy Barrels. With the same loads and bullets, he is consistantly 200fps faster than mine. Another factor here is, after he fires a cartridge in his rifle, I can easily chamber the fired case in mine, and vice versa for his. I see this often.

Jerry

Well like I said, I've been chronographing since '75 and a lot of that is with multiple rifles of the same cartridge and the same load. I'm not doubting what you or batsche is saying at all but quite frankly I've not found that much difference, not even once. Right now of the multiple rifle same cartridge combo's I've got three .22 Hornets, six .223s, four 6.5x55s, three 30-30's, seven .308Ws, six 30-06s, three 7.62x39s, four 7.62x54Rs, three 7.65 Argentines, three 8x57s and four 45-70s. Plus in past years I've had multiple 22-250s, 243s, 270s and .303s.

With the same loads there are three ways in which I've gotten 200 fps difference between rifles with the same loads. That is when there is 4" or more variation in barrel length. When one barrel has had many, many more rounds through it and it is worn, particularly the throat. And last is when one load is chronographed on one day in one rifle and then on another day the other rifle is chronographed.

In the last case, if chronographing on different days, we must take great care to see that the set up is a consitent distance from the muzzle and we must note the other conditions. It may seem to some that is not necessary but it is if one is going to compare loads chronographed on one day to loads on another day. I have probably watched several hundred chronograph users "set up" over the years and have only seen one other user actually measure the distance from the muzzle/bench to the screen. If you just want an idea of how fast the velocity is then it doesn't make a lot of difference. If you want to make valid comparisons then you should take pains to make sure the set up is consistent.

Let me mention Chrony's in particular here. I've seen a lot of Chrony's unfolded, screwed onto a tripod and just set somewhere out in front. A lot of them are not completely unfolded. With the very short csreen spacing it does not take much to induce a large error. I've had numerous Chrony owners ask to test them in tandum with my Oehler M35P or the M43. When i place the Chrony I make sure it is completely unfolded. On numerous occasions the same ammo through both the Oehler and the Chrony was 40 - 75 fps less than what the chrony owner had just shot with the same rifle/ammo. There was that much error induced. BTW; All the Chrony's had very acceptable average velocity readings compared to the Oehlers. I use a 4' screen spacing (2' for the Proof screen) with my Oehlers. It takes very, very little movement back or forth to induce a large fps variation.

Anyways, back to the topic. I do not doubt a 200 fps spread is possible but I still don't think it is very common, at least I have not seen it yet. But who know's, I could see it tomorrow.

Larry Gibson

Years back I had an opportunity to chrono through my Oehler 33 a 4", a 61/2" and an 8 3/8's inch Model 29's... all same .44 Magnum R-P ammo... the speeds expected were found in the reverse order for those 3 revolvers.

I have a Kimber 8400 270 WSM and a Tikka LHT WSM. Both have 24"bbls. Well the Tikka is a half inch longer. With Federal 140 gr Nosler factory loads, I see a SUBSTATIAL difference in velocity. The Kimber cronographs 3120 fps. The Tikka at 2890. That is over 200fps difference!!!! But, the Tikka has an exceptional leade as compared to the Kimber. Almost 0."18" more leade in the Tikka. Fortunately the Tikka is EXTREMLEY accurate. I call it my "ONE HOLER".
Shit happens, but is not always dissapointing.
Every rifle is different.

We chronographed 5 Mannlicher Luxus rifle, all brand new, in 270 Winchester, using Norma 150 grain SP ammo.

All from the same lot, and at the same ime.

The fastest rifle was 150 fps faster than the slowest one!!??

We have had, on a number of occasions, seen some rifles that tend to exhibit faster velocity than we normally get, and some that do not seem to be able get any decent velocity.

This goes right across the caliber range.

We have a 300 RUM Senderao that is faster than a 30-378 Weatherby.

I am afraid these things are very hard to explain.

Yup, strange things do happen, but I guess my questions are; how often? Or is this more prevelent than expected?

Larry Gibson

I think this is more prevalent than we expect.
But, not many of us actually can compare several rifles together.

In fact, all one has to do is compare different loading manuals, and one would see the differences they get from their test rifles.

quote:

Originally posted by Jerry Eden:
Larry, I don't believe that this issue is rare. As a matter of fact my best buddy and I have 2 Remington 700's in 223 Rem, 24" Heavy Barrels. With the same loads and bullets, he is consistantly 200fps faster than mine. Another factor here is, after he fires a cartridge in his rifle, I can easily chamber the fired case in mine, and vice versa for his. I see this often.

Jerry

It would be really interesting to have these two rifles compared internally. I would love to see a comparison of the chamber casts, a slugging of the bores and a comparison of the bore finish.

quote:

Originally posted by Saeed:
I think this is more prevalent than we expect.
But, not many of us actually can compare several rifles together.

In fact, all one has to do is compare different loading manuals, and one would see the differences they get from their test rifles.

Loading manuals do not use the same loads as do other loading manuals, i.e. exactly the same load. But here's what I'm saying. Some years back there was a considerable discussion on some barrels being "fast" barrels. The problem with the analysis is one would say he got so and velocity and some one else across the country claimed so and so velocity a hundred or so fps higher. No one at the time seemed to have the ability to test multiple rifles of the same cartridge with the same barrel length using the same ammo at the same time under the same conditions. I was able to do just that some time after the discussion.

I was able to chronograph the same loads in several rifles during the same test session. Not only do I have multiple same cartridge rifles of my own but for a number of years I had free access to an arms vault with numerous weapons available. I was able to conduct multiple chronograph tests with M16A1/A2s, M4s, M14s, M1s, M1 Carbines, M1944s, SKSs, AKs and M24s. The east number of same cartridge weapons during the test was 3 and the largest was 12. The largest velocity spread I recorded using a M35P was a match M16 with a new 8" twist 20" barrel which recorded 154 fps more with M855 ammo than the average of 5 other M16A2s with 7" twist barrels. The match M16s chamber was to minimum spec for M855.

Now if there was going to be a wide variation of velocity I thought it would be out of the M1944s since there were 3 different countries represented and a wide variation in groove depth. I tested 6 M1944s (2 from each country) using some Russian "L" ammuntion. I was quite surprised that the variation from the highest to the lowest was a little more than 100 fps.

I certainly agree that there is going to be a variation. Heck, If you run 3 ten shot strings through the same rifle with the same ammo consecutively odds are that the average velocities will not be the same. How much variation depends on the consistency of the ammuntion and the test sample. If you shoot 3 shot strings more than like the spread will be higher than if you ran 5 shot strings and ods are that 10 shot strings will have even a lower spread. That's why a larger sampling is more indicative of the real accuracy potential of ammuntion. You will get a larger group, a larger ES and a larger SD most often as there are always exceptions.

Point is; I've conducted a lot of multiple, same cartridge, same ammo tests and have yet to see a 200 fps spread let alone a 200+ fps spread. I don't doubt that it is possible but I have not seen it. Perhaps I am lucky, maybe tomorrow i will see it. My experience tells me a velocity spread from a high to low of 100 fps is fairly common but still not the norm. A variation of more than that up through 150 fps is possible. But 200 or 200+ fps variation would be a rare occurance. Not improbable but rare. Just my thoughts based on my experience.

Larry Gibson

quote:

Originally posted by Larry Gibson:
...200 or 200+ fps variation would be a rare occurance. Not improbable but rare.

Rookie!

Hopefully a point of interest. I have two 7x57s that were built by me with indentical 19" replacement barrels. There is a diferrence, however: there is about a .075" throat, differential. The velocity results are such that with one load the Styer Mauser might be 19' per second faster and with the next load The Columbian mauser is 23' per second faster.
I remember the fast barrel slow barrel thread. Was there anything in it that indicated that a two inch difference in barrel length could cause the large velocity variances we're discussing? roger

quote:

Originally posted by Hot Core:

quote:

Originally posted by Larry Gibson:
...200 or 200+ fps variation would be a rare occurance. Not improbable but rare.

Rookie!

Another gem like a turd in a punch bowl!!!!!


Pathetic and Pitiful

Respectfully,

quote:

Originally posted by bartsche:
Hopefully a point of interest. I have two 7x57s that were built by me with indentical 19" replacement barrels. There is a diferrence, however: there is about a .075" throat, differential. The velocity results are such that with one load the Styer Mauser might be 19' per second faster and with the next load The Columbian mauser is 23' per second faster.
I remember the fast barrel slow barrel thread. Was there anything in it that indicated that a two inch difference in barrel length could cause the large velocity variances we're discussing? roger

There are a number of variations that effect the velocities, especially when you throw in another ammuntion as you did. Hard to say though. A very recent test of Winchester factory 7.62x54R 180 gr SP ammo in 3 Mosin Nagants showed some variation but nothing that wasn't expected.

I chronographed the ammo in the 3 rifles in about a 1 hr time period. 10 shot strings were fired. The first rifle is a Russian M91/30 sniper (real one) with and excellent bore that slugs at .303x.312 in it's 28.5" barrel. The sencond rifle is a Finnish M39 Sako rebuild in excellent condition with a 27' barrel that slugs out at .300x.310. The Third rifle is actually a Carbine; a Type 53 Chinese that i brought home from Viet Nam. It's barrel is counter bores giving it an effective barrel lenght of 19.5". The bore is in very rough shape and slugs at .308x.316.

The average velocities with the Winchester ammo were; 2608 fps for the M91/30, 2599 fps for the M39 and 2406 fps for the Type 53. The SD and ES were pretty much the same for the M91/30 and the M39 but the Type 53 gave the largest SD/ES which was expected due to the rough oversize bore. Still the SD/ES was 21/56 for the Type 53 which is still very acceptable.

One would have expected a larger velocity spread than the 9 fps between the M39 and the M91/30 given the 1.5" longer barrel of the M19/30. Given the "usual" tables of difference in fps per inch of barrel one might have expected the M91/30 to be 40-50 fps higher than the M38. However, the tighter bore of the M39 apparently came into play.

The Type 53 with it's 7.5 - 9" shorter barrell. gave only 200 fps less velocity that the longer and tighter bored M91/30 and M39. Would have been interesting to see what that lot of Winchester ammo would have done in a M1944 with a much better bore.

Point is that there are indeed numerous things that can effect the velocity of a given ammo in a given rifle. I also think a powder that is compatable with the actual effective barrel length and expansion ratio also can make a considerable difference in velocities between different, although small, lengths of barrels.

Larry Gibson

quote:

Originally posted by TEANCUM:

quote:

Originally posted by Hot Core:

quote:

Originally posted by Larry Gibson:
...200 or 200+ fps variation would be a rare occurance. Not improbable but rare.

Rookie!

Another gem like a turd in a punch bowl!!!!!


Pathetic and Pitiful

Respectfully,

TEANCUM

Got to ask ourselves given all of the times Hot Core has blasphemised chronographs and their use, has repeatidly stated he does not use one and in general denegrates anyone who does use a chronograph....just how and/or what the hell does he know about a 200 fps variation between barrels? How does he measure velocity? Must be with his tried and true CHE/PRE........again Hot Core makes comments that offer nothing to the topic at hand, just inane accusations and personal attacks. Let us, here at least, just ignore him and his obvious comprehnsion dysfunction.

Larry Gibson

quote:

Faster burn/shorter barrel) and that the higher velocity with a longer barrel was due to the higher velocity with the slow burn up the barrel?

Not really. No matter the burn rate, peak pressure is attained within a couple of inches of bullet travel and most of the powder is burned soon after. A longer barrel simply allows the bullet to continue to be pushed a tad longer.

Jim C

That's not quite the case. s you mention the slower burning powder is going to continue burning and "pushing" the bullet faster the longer the barrel is but the peak pressure is occuring farther down the barrel than many previously realised. This if given a large enough case capcity to allow the slow burning powder to obtain the same peak pressure as say a medium burning powder.

With modern slow burning powders the point of peak pressure gets pushed farther down the barrel simply because it takes longer to attain that peak pressure and the bullet is moving during that time. If comparing say 4895 and 4350 in an '06 with 180 gr bullets the location of the peak preassure is a noticeable distance farther down the barrel. Exit pressure at the muzzle will also be noticeably higher. An Oehler M43 PBL provides not only the pressure curve which is a very quick "visual" but also data of the area under the pressure curve and data on the rise of the pressure curve. All 3 of those tell the story.

The longer barrel does indeed allow the bullet to be pushed longer which to me is benificial with 24 - 26" barrels. A few good examples are the increased velocity of the .308W in 27-30+" Palma barrels, the very substantial increase in velocity out of a 30" M10 Ross .303 over the SMLE and the increased velocities possible in the '06 with a 26" barrel vs a 22" barrel using slow burning powders that provide 100% loading density at 60 - 62,000 psi.

Finally a last example is the powders used in Hornady's SuperPerformance ammo that has a longer pressure curve yet mostly burns completely in standard for cartridge length barrels. New technology is finding better ways to measure what is happening with internal ballistics and with powders. someday perhaps us reloaders will have access to such improved powders. However, right now the newer ones available are provider much improved ballistics. That's not to say that the old standbys still don't perform either.

Larry Gibson

We had a Remington 40X, with a 26 inch barrel, that was brought in here for load development.

It was bought in the 70s, and had a wooden stock.

Try as much as I could, I could not get it to come anywhere near the velocity we were getting from other 40X rifles we had.

It was in 22-250 Remington chambering.

It is problem was it reached maximum charges several grains less than other rifles.

We checked the bore with a bore scope, and could not find anything wrong with it.

It shot very accurately.

Only problem with it was the reduced velocity.

With some powders, it would reach maximum with up to 7 grains of powder less than other rifles in the same caliber.

We have had a custom made 308 Winchester, with a European barrel of uknown make, that had much higher velocity than any other 308 we have evr had.

It shot terrible, and one could increase the powder charge until the primers fall out of their pockets - without any other sign of high pressure.

We have had European made rifles, in 243 Winchester, that would blow the primers on starting loads, as well as factory ammo.

One can get very strange results sometimes with differing rifles.

quote:

Originally posted by the doughnut king:
...all of the times Hot Core has blasphemised chronographs and their use, has repeatidly stated he does not use one and in general denegrates anyone who does use a chronograph....just how and/or what the hell does he know about a 200 fps variation between barrels?

As I've stated numerous times in response to this total STUPIDITY, I used Chronographs for many years - before - it dawned on me they are pretty much a total waste of my time. Anything a person can get from a Chronograph can easily be "guesstimated close enough" that it can be used to help get the long distance Point-of-Impact verification started. Then it is simply a matter of recording the Shot-Data adjustment "Clicks" for the various distances and keeping them with that specific Load and that specific rifle.

Since a "lack of memory" is normal with this doughnut-eating radar-running FOOL(who totally wasted $$$HUGE$$$ on a M43 which can not be calibrated, uses guessed at dimensions and who's worshiped M43's credibility was totally DESTROYED by the good-old, never-fail, always-reliable, repeatable, inexpensive CHE portion of CHE & PRE in the totally unbiased, GLOATING Thread) - I'll keep a link to this thread so it will show his memory is as useful as all of his doughnut powder stained comments.
-----

It is certainly not uncommon to have Velocity spreads of 200-250fps in a series of rifles coming off of the same production line, sequentially serial numbered in the exact same Caliber with the exact same barrel length. It would be extremely rare not to see variances of 100-150fps by looking at "any" 6 in a row from that same Lot.

Velocity measured with a specific Load in a specific rifle only applies to that exact rifle and that exact Load. To drawn any further inferences or conclusions is worthless. Just the way it works, regardless of how many want to think it works differently.

Saeed

Am I seeing perhaps a "trend" with European made bores?

Indeed we can see some very strange things occasionally. Many years ago when I was at the range with my Oehler M33 set up a fellow member brought over a Winchester M88 in .284 Winchester and wanted to chronographed the factory ammo he was using. The rifle just had the iron sights on it and the fellow said he'd had it several years and only shot a couple boxes of factory ammo through it. He said it shot "ok" but not real well. I shot the 1st shot and noticed 2 things right off the bat; no hole on the target paper (100 yards using a 25 yard pistol bullseye) and the lever was a little stiff operating when the bolt was first unlocking.

I then looked at the case and there was visable smoking around the very flat primer. I then ran the time numbers on the chronograph and checked the chart for the velocity. It was just not quite 300 fps faster than the advertised velocity for that ammo. I fired 2 more shots with pretty much the same results except the 3rd shot hit the target paper making the classic keyhole out line of the bullet.

I pulled out my bore scope and checked the bore suspecitng perhaps severe fouling. What a shock to find absolutely no rifling what so ever! Apparently the barrel had slipped through with just the bore at .276" (I slugged it). The rifle was shipped back to Winchester and they rebarreled it offering no comment. It shot just fine with the new barrel at expected velocities. Strange things indeed!

Larry Gibson

[QUOTE] Anything a person can get from a Chronograph can easily be "guesstimated close enough" that it can be used to help get the long distance Point-of-Impact verification started.

Wow Hotsh$t

You are in rare form today. Apparently you've had a bad experience with a chronograph along the way maybe you ended up shooting yours by mistake and are harboring a grudge against them. I love the part about "GUESSTIMATED". Classic idiocy and very DANGEROUS.

Some of the new guys on this thread should completely disregard this post and well ....................all the posts that Hotsh$t makes as they are dangerous, pitiful, and pathetic. Reloading is too serious a hobby to go around guessing in the process. DO NOT FOLLOW HOTSH$T'S ADVICE. This is an old fart that is well intended.......some of the time but has had some bad experiences over the years and has become unbalanced in the pursuit of his dangerous opinions. He lacks the true experience that you, and new reloaders, can find helpful and relies on his old time OPINIONS.

Dangerous and to be avoided at all costs.


Respectfully,

bartsche ----- I shoot two .358 STA's, both custom Model 70 Winchesters, one from the Winchester Custom shop and one from a custom gunsmith from Cheyenne Wyoming. The difference in the speed with the same loads is always between 50 and 150 fps. I also shoot two .270 WSM's that have differing speeds for the same loads. I chronograph 99% of all my loads on a Oehler 35-P. As far as the usefullness of the chronggraph, it depends on what you want to do and how you want to get there. You can certainly not use one and not know speeds of loads, and get accuracy, but the shooting time would be considerably more. Honestly I am addicted to my 35-P and feel naked without it when developing loads. Knowing the speeds from manuals or information gained here on AR helps, but until I verify on the 35=P

bartsche ----- I shoot two .358 STA's, both custom Model 70 Winchesters, one from the Winchester Custom shop and one from a custom gunsmith from Cheyenne Wyoming. The difference in the speed with the same loads is always between 50 and 150 fps. I also shoot two .270 WSM's that have differing speeds for the same loads. I chronograph 99% of all my loads on a Oehler 35-P. As far as the usefullness of the chronggraph, it depends on what you want to do and how you want to get there. You can certainly not use one and not know speeds of loads, and get accuracy, but the shooting time would be considerably more. Honestly I am addicted to my 35-P and feel naked without it when developing loads. Knowing the speeds from manuals or information gained here on AR helps, but until I verify on the 35-P, I don't trust my loads totaly. This is the way I do it, for what it is worth. Good shooting.

quote:

Originally posted by phurley5:
Honestly I am addicted to my 35-P and feel naked without it when developing loads. Knowing the speeds from manuals or information gained here on AR helps, but until I verify on the 35=P

X2 roger

quote:

Originally posted by Hot Core:

It is certainly not uncommon to have Velocity spreads of 200-250fps in a series of rifles coming off of the same production line, sequentially serial numbered in the exact same Caliber with the exact same barrel length. It would be extremely rare not to see variances of 100-150fps by looking at "any" 6 in a row from that same Lot.

Upon what experience do you base this opinion?

We have a number of identical rifles in 223 and 308.

They are from BRNO and Sako, and all the rifles are brand new, so the test should be interesting.

I am going to try both factory ammo and reloads in them, and see what we get.

The testing should indeed be interesting, looking forward to the results.

Larry Gibson

I have found 14 Sako S491 rifles in 223 Remington.

We have several types of military ammo. I am going to start off with these, and see where that gets us.

I have also found that we have 14 different types of factory 223 ammo.

And as we are only interested in seeing the velocity variation between them, I am going to shoot 3 rounds of each type of ammo in each rifle over the chronograph.

quote:

Originally posted by Saeed:
I have also found that we have 14 different types of factory 223 ammo.

And as we are only interested in seeing the velocity variation between them, I am going to shoot 3 rounds of each type of ammo in each rifle over the chronograph.

Saeed

That should be close enough to tell a tale. Waiting for the results.

Larry Gibson

quote:

Originally posted by Jerry Eden:
Larry, I don't believe that this issue is rare. As a matter of fact my best buddy and I have 2 Remington 700's in 223 Rem, 24" Heavy Barrels. With the same loads and bullets, he is consistantly 200fps faster than mine. Another factor here is, after he fires a cartridge in his rifle, I can easily chamber the fired case in mine, and vice versa for his. I see this often.

Jerry

Bingo.