Featured Blowback and dirty cases

Discussion in 'Glock Forum' started by tinbucket, Mar 12, 2018 at 3:09 PM.

  1. tinbucket

    tinbucket Well-Known Member

    This really fits most all semi auto handguns.
    On Guns and Ammo TV just a few minutes ago I caught the tail end of story on hand guns and recoil etc.
    Upon firing before any unlocking, of the barrel, and unlocking the slide, and rear movement, there was a vertical high pressure escape, of gas through the small spot, in the top of the slide.
    I think the gun was a Glock; at any rate, it was black, square, and plastic.
    We've all seen handgun ammo cases with black smears down the side of the shell casing and dirty guns as a result.
    It means to me not enough pressure or the brass case to expand enough to seal at the mouth of the cartridge.
    We've seen it on revolvers too.
    I don't remember seeing it as much in old nickel .38 cases which are thinner, as much.
    I think it is party the result of marketing forces, for lawyer proof safety with lower pressure and lower velocities.
    In my .357 my 125 grain loads sea and there is no back smear along the shell casing from burned powder. Factory loads there are smears and toward the thinner part of the chamber next to the cylinder.
    In my 9mms I don't see much to any in hand loads or in NATO loadings.
    I looked though a pie of 9mms a while ago and some, the Winchester cases have more smear of carbon.
    I don't like the idea of escaping gas in my guns. I have had pieces, of whatever, hit e in the face and on my arms and hand over the years. Never caused any problems but a bit of irritation mostly.
    So most of my loads are hotter than factory, and data from old manuals.
    And I see less blow by.
    Are today's guns so weak that the weak loads from factories, and in current manuals is really called for or are Lawyers and bean counters the reason?
    How do you establish your loading data or do you, as most of us do just follow the manuals ideas or go from there.
  2. locutus

    locutus Well-Known Member Supporter

    The guns are not weaker, the lawyers are just smarter.

    Like you, most of my loads are above factory spec and above NEW BOOK maximim. But below old book max.

    Of course, most of my loads were worked up before their were more lawyers than hand-loaders.

  3. Sniper03

    Sniper03 Supporting Member Supporter


    I have a rule when loading Rifle or Pistol ammunition.
    First of all reloads are the number one cause of catastrophic events as they are refereed to in the industry. "A Blow Up" for most of us.
    But my Rule is I never load to the max limit! And have found there is no need for max loads to begin with in my opinion. There are so many good effective bullets out there that perform phenomenally they do not need to be traveling at Warp-3 speeds anyway.
    My rule with the rifle is I start off half way between the minimum and the middle of the recommended load. Then work my way up until I achieve maximum accuracy and performance. Normally I find the correct load for the weapon somewhere over the Middle Load and Max. Load. And that also assures me, I am well within the safety standard for that particular caliber and weapon. And I also do not experience Blow Back on the cases from the round being fired! Of course resizing and proper loading of the Brass is very critical. And Good Up to Date Loading Manual and Good Scales are a necessity.
    And one other "Important" thing is a loading area without distractions of any type!:)
    Last edited: Mar 12, 2018 at 6:50 PM
    Dallas53 likes this.
  4. locutus

    locutus Well-Known Member Supporter

    Sniper, I agree and disagree with your post.o_O

    For a varmint or target rifle, I will gladly give up 100-150 FPS of velocity for extreme accuracy.

    For a big game hunting rifle, that does not need extreme accuracy, I will give up an inch of accuracy for 150-200 FPS of velocity.

    As for "modern, up to date manuals" I will try their loads against older manuals.

    As an example, I have a 9MM load, worked up 35 years ago, that gives me 1350-1375 FPS with 115 bullets.

    Using old manual data. loading to max with the new manual uses .6 grain less powder and only makes 1225-1250.

    Using this load, I've compared 30 year old powder to new and it's the same

    All loads must be worked up to from below, very carefully, but the (new) manual is usually more of a guideline than a holy writ. ( to me, at least)
    Dallas53 likes this.
  5. Dallas53

    Dallas53 Well-Known Member

    Tinbucket, i have warned you about getting some new up to date load data manuals, and quit using that old information. as others have also advised you in the past as well. you are fixing to either get yourself or someone else hurt.

    here's some reading you need to read, before you end up blowing up a gun and all of your fingers! i found this on another forum.

    YES, A WARNING! I received a cautionary bit of IMPORTANT ADVICE last night while visiting the Cast Boolit web site. The first two reloading manuals I bought, in 1972, were the Speer No. 8 and the Lyman 45th Editions, both published in 1970. It has become known over time that the data collected and published in the Speer No. 8 Manual is now SUSPECT AND IN FACT DANGEROUS in regards to various cartridges, especially handguns.

    In the Speer No. 10 Reloading Manual, page 107, it is stated...."The data in the Number 8 and earlier manuals was based on primer appearance, ease of case extraction, and case head expansion. These methods are still valid, and are the only ways the reloader can estimate the safety of his loads without some rather complicated laboratory equipment."

    A member of Cast Boolits, Dalles53, was alert enough to inform me that the Speer No. 8 Manual data had been found to be erroneous and very dangerous when new "pressure testing" data became available. Revisons were subsequently published in the Speer No. 9 Manual.

    I did a comparison of .38 Special and .45 Colt data between my copies of the No.8 and No.10 manuals and even looked at other newer manuals from Lyman, Hornady and Lee, which all confirmed that the Speer No. 8 data was erroneous and should be considered dangerous. Some of my comparisons disclosed MAXIMUM loads from the No.8 Manual for .38 Special cartridges were as much as 2 1/2 grains higher than the newer "pressure barrel" data. Differences of 1 to 2 1/2 grains of powder in various loadings represent as much as 12 to 25 percent higher powder weights than are recommended by todays instrumented MAXIMUM LOADS!

    Dalles53 had a Speer No. 8 Manual load that was 1 grain below MAXIMUM tested by a friend who works at a commercial ammunition manufacturer. The round(s) disclosed an instrumented pressure in excess of 67,000 units of pressure! Dallse53 was astounded as he had not experienced any extraction or primer pocket problems or signs in his S&W Model 19. A friend of his shooting this same load in a S&W M28 did have extraction problems which prompted Dale to have the load tested.

    I am most appreciative for the "heads up" advice of this gentleman, Dalles53 from Cast Boolits, who was very alert and diligent in catching and informing me of this "old manual data" danger that is still lurking in the tall grass of ignorance.

    and you need to understand that how pressure was measured years ago is much different than it's done currently. the equipment is much more accurate than past equipment. this is from Speer's website.

    The differences in load data reflect changes in the way pressures are measured and changes in components over time. Loads developed in the past reflected the current state of pressure measurement and the components available then. Things change, so always use the latest data. Not all bullets are built alike either, so data for a "Brand-X" bullet will produce different pressures than a Speer bullet. Use data from the company that made your bullet.
    Chainfire, jigs-n-fixture and Fred_G like this.
  6. tinbucket

    tinbucket Well-Known Member

    Always work loads up in steps from manuals.
    I have a few .270 Wby 90 grain Speer loads, triplex at over 4,000 fps. 4,400 I think.
    Bullets do not make it to the target is the only problem. Watch them turn to a haze not too far out. Need to start with .30-378 case. Not sure of what powder I could use. Not going to do it anyway.
    I load rounds for semi autos on the warm side.
    I am not satisfied with pedestrian performance.
    Every time I hear condemnation of the .220 Swift, the .30-378 Wby and how about some of the big shot gun shell sized rounds o one o our Posters. I like to stretch performance safely. The older Wby Rifles had longer free throats, more powder, and higher velocity same pressures.
    I have not found an economical source or a 9x25 mm Dillon barrel for my Delta Elite, yet.
    I understand the round is real barn burner.
    Increasing range, means higher velocities, as all bullets minus atmosphere at to the ground, with the same bc, at the same time, if fired in same trajectory. So increase the velocity and that bullet hits the ground a lot further out.
    Instead of aiming at the moon with a .30-30 to hit 200 yards out a .220 swift is dead on with scope about 1 inch high, or thereabouts at 100 yards. Imagine a better bullet at 5500 fps. Dead on at 100 and a tenth of inch low or less, at 200 yards. Out west game is days walk away over gullies and canyons but you may not be able to get any closer.
    A lot of western Gun Owners, no sporting 30 inch barrels and heavy bench rest stocks, or sorta but still some mundane calibers like the ,338 Winchester.
    Then there is the two mile shooting contest on tv, really a bit short at 1900 yards. Some .50 BMG rounds and pop culture .40s as used by Snipers.
    My thoughts, I would like to to try it is semi auto Barret, with supplemental recoil adsorbers with 34 inch to 40 inch barrel, chrome lined, increased free bore, cut rifling,to match velocity and bullet, and recoil springs to match, muzzle break and increased velocity, from appx 2900 fps with 750 grain bullet, to 3800 fps maybe more. Would require a tougher bullet , and more bc design but I bet there is one out there..
    The Barret might not be up to the job as it is stamped sheet metal but a good machinist can do anything with hunk of metal. I'm not perhaps Brother would be interested.
    However the Grim Reaper will gt to me before this pipe dream would be accomplished.
    Last edited: Mar 12, 2018 at 9:25 PM
  7. Dallas53

    Dallas53 Well-Known Member

    Tinbucket, i'll counter your velocity opinions on distance, with some proven performers in extreme long distance target shooting....

    the 6.5 Creedmoor. bullet weight and velocity.
    120 gr (8 g) AMAX 3,020 ft/s (920 m/s) 2,430 ft⋅lbf (3,290 J)
    143 gr (9 g) Hornady ELD-X 2,710 ft/s (830 m/s) 2,283 ft⋅lbf (3,095 J)

    the 260 Remington.
    120 gr (8 g) AccuTip BT 2,890 ft/s (880 m/s) 2,226 ft⋅lbf (3,018 J)
    140 gr (9 g) Soft Point 2,750 ft/s (840 m/s) 2,351 ft⋅lbf (3,188 J)

    the 6.5x47 Lapua.
    6.7 g (103 gr) Scenar 939 m/s (3,080 ft/s) 3,087 J (2,277 ft⋅lbf)
    8.0 g (123 gr) Scenar 880 m/s (2,900 ft/s) 3,098 J (2,285 ft⋅lbf)
    9.0 g (139 gr) Scenar 820 m/s (2,700 ft/s) 3,028 J (2,233 ft⋅lbf)

    the 6.5-284 Norma.
    125 gr (8 g) Partition 3,000 ft/s (910 m/s) 2,497 ft⋅lbf (3,385 J)
    142 gr (9 g) Hodgdon 2,850 ft/s (870 m/s) 2,557 ft⋅lbf (3,467 J)

    most of these are shot at 1000 yards or more, accurately! they are no barrel burners either for the most part from most are reporting of barrel life and erosion.

    i think your velocity argument is incorrect and false, in light of what experienced handloaders and shooters are showing that it's not needed, nor necessary.

    your quote Tinbucket:
    I have a few .270 Wby 90 grain Speer loads, triplex at over 4,000 fps. 4,400 I think.

    exactly where did you get this load data? source (load data manual and edition.)? exact powder used? powder charge used?
    Last edited: Mar 12, 2018 at 9:56 PM
    jigs-n-fixture likes this.
  8. tinbucket

    tinbucket Well-Known Member

    I worked up those loads in the seventies. They are my own and I won't share them.
    They are triplex loadings.
    I talked about them in reloading a long time ago.
    The idea that slower has better range and accuracy, is only true when the load matches the twist etc.
    And you can't change the truth that you drop any 2 or 100 objects with whatever weights they will hit the ground at the same time and that any bullet regardless size will hit the ground at the same time whether 100 grains or 40 grains, just different distance dependent on velocity, fired at the same trajectory.
    I suppose you thing the .22-250 is superior to the .220 Swift too or the .257 Weatherby.
    My edit going back to the original subject just went poof mid word. I'm not going to finish it again now.
    Last edited: Mar 13, 2018 at 1:22 AM
  9. Dallas53

    Dallas53 Well-Known Member

    so that would be a no then? okay dokay! you are under no obligation to answer my questions. that is entirely your right and option to answer them, or not. i was interested and curious, as i'm sure other might be as well, how you were getting almost 1000 fps more, than some of the highest listed velocities for that cartridge with that weight of bullet, than the published load data manuals are showing.

    carry on.:)
  10. jigs-n-fixture

    jigs-n-fixture Well-Known Member Lifetime Supporter

    Load data changed not because of lawyers, but because of engineers. The load data got milder, when Ohler designed and started selling, high speed pressure sensors, and started sellling them to the reloading supply, and equipment manufacturers.

    When the pressure tranducer setups hit, folks discovered that the old systems, which relied on metal flow, were under recording the actual pressures.

    When an engineer designs a chamber, bolt, barrel, combination, they are working to design a pressure vessel system. They, design that system for a stated maximum pressure, plus a safety factor, to account for the occasional lower strength run of steel, slight errors in machining, etc.

    When the transducers hit, the load data went down, to keep the pressures within the SAAMI maximim for that clambering. This is to assure the loads do not over stress the actions it is chambered in. Now some engineers used higher safety factors, and most commercial actions were designed for the highest pressure clambering the particular series, design will see in all the various chamberings it will be built in.

    I load, for the 257AI, it has a SAAMI pressure rating of 58-kpsi, it is in an identical action, barrel profile, etc, as the 25-06, which is rated for 62-kpsi. I feel safe pushing the envelope on the 257AI, because I know the bolt will handle the higher pressure of the 25-06. And since the chamber on the 257AI, is a bit smaller than the 25-06, the chamber will also handle a bit more pressure. So, I load to velocities normally seen with the 25-06.

    The problem with developing higher than manual pressure loadings, is that you could be over stressing an action for years, and causing fatigue damage to the bolt lugs, and never know it, unless you routinely check for stress damage to the bolt. One day, it may reach a final failure state, and come back into your forehead. Those who investigate the incident, will blame it on the last round fired. While it will be the result of long term slight over pressures, resulting in a final catastrophic failure, at no higher pressure, than it had seen for the last thousand rounds.

    When I was in engineering school, and taking “Mechanics of Materials”, which is where you first learn about such things, one of my buddies had an axle failure on an off road buggy he built, with a Chevy V6, backed by a Volkswagen transaxle. The failed axle had a beautiful polished surface, over about sixty percent of the failure, which indicated the damage had been occurring over a long period of time, and one final blip of the throttle, had been the last straw.

    Same thing can happen with over stressed components caused by overpressure loadings. All of a sudden, the gun goes boom, and blows up in you face. And folks blame the gun, or reloads in general. Not a lifetime of overpressure loads.
    AZdave, tinbucket, JTJ and 1 other person like this.
  11. JTJ

    JTJ Well-Known Member Supporter

    Shoot a blow back operated firearm and you will really get dirty cases. I used a few sources for data and have a new manual but I load my 9mm to max but not +P. I am usually under max on rifle loads. I checked my old loads against the new manual and am OK. I am currently working up some 357 magnum loads to be used in a rifle but will still work in a revolver. I will stay below max on those.
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  12. tinbucket

    tinbucket Well-Known Member

    getting way away rom the subject again
    Last edited: Mar 13, 2018 at 11:59 PM
  13. Dallas53

    Dallas53 Well-Known Member

    curious as why you would think that? what people are discussing, is in direct relation to the subject of the thread and to your questions in your first post. :confused:

    people are trying to answer your questions, and provide you the information you are looking for.

    frankly i don't even see the thread having drifted in the least.
    Chainfire likes this.
  14. locutus

    locutus Well-Known Member Supporter

    Remember when discussing preasure that CUP and PSI are different.

    The .270 was designed for 52- 54K CUP. That works put to roughly 66-68 KPSI.
    Dallas53 likes this.
  15. tinbucket

    tinbucket Well-Known Member

    That is what I said. You're right :)
  16. Dallas53

    Dallas53 Well-Known Member

    also the equipment used to measure pressure have gotten much better and more precise. this is part of the reason behind the variances in pressure readings in the past and those today.

    another important thing about using old load data books is the powder itself. powder manufacturers make changes in the chemical composition of their powders all the time. so even a powder that was available thirty, forty or even fifty years ago, using the same trade name and type, is not the same powder, and that is the reason powder charge weights can vary.

    thinking you can use load data from many years ago, is just flirting with disaster. now, of a person was using fifty year old powder that they had stashed back, and if it was still good, then using fifty year old load data might be acceptable.

    i keep my old load data books simply for reference, information, and nostalgia. i have some of my old books that show loads for cartridges that probably some may not have ever even heard of!
    locutus likes this.