50cal
Member
That's a lot of measuring. There are better more consistent ways to vet it. So if it mics ok then it shouldn't 'push' when it hits the feed ramp?
Now now 50cal, perhaps a review of the OP may take some chill out of your post.50cal said:While some of the concepts mentioned in the thread have relevance in some capacity ... It makes for interesting discussion perhaps but little in terms of real-world application. If the cartridge is safe, runs reliably, produces consistent results and is accurate, the other factors become almost obsolete. We are seeing more speculation and less legitimate proof.
The reason why I titled the thread "Concepts and Discussions" was because that's what I wanted to do with some members, have discussions about advanced reloading concepts. A concept is an idea of what something is or how it worksbds said:Advanced Reloading Concepts and Discussions
We are in the "loose" phase of this thread and over time will "fine tune" so we canWe can start off loosely and perhaps over time fine tune the thread
so it becomes an indexed quick reference for us to use. After successful discussions, I can maintain an indexed summarized linked listings post with the necessary disclaimers Walkalong can be happy with
This thread is for reloaders who enjoy the minute details of reloading to OCD levels in pursuit of accuracy. If you are that person, come right in and post away. If utmost accuracy is not that important and minute of gong is good enough for you, read on.
What you measured was leade or freebore, the distance from the chamber to the start of rifling. Many factory barrels have longer leade and slower start of rifling (angle is gradual) like Glock/M&P and most match barrels have shorter leade (or almost none like my Sig 1911 and latest Lone Wolf G23 40-9 barrel) and quicker start of rifling (angle is sharp).LeftyTSGC said:9mm ... STAR30M 9mm (Mil Spec)
I measure the distance (this was hard) from casemouth to lands, after 10 measurements i found it to be .145in. that is a lot of jump space but being mil spec i assume it was designed to handle most types of ammo ... used this to set my OAL of each type of bullet independently.
Yes, bullets will have different nose profile (ogive), even for the same RN profile and end up with different bullet base/bearing surface length which will hit the start of rifling at different OALs.I have noticed that you cannot group bullet types but need to find the OAL for each bullet.
If you are using mixed range brass, sorting by headstamp may not ensure uniformity. Instead, sorting by resized case length would better help with ending up with more consistent OAL in terms of amount of bullet's bearing surface sticking above the case mouth when the rounds are chambered vs start of rifling. Can you picture that?I sort my brass by headstamp to maintain as much uniformity as possible.
Depending on the bullet manufacturer, consistency of bullet nose profile will vary. Since it is the bullet's bearing surface that engages the rifling (and not the nose tip), using the same OAL with a particular random sample bullet may not ensure consistency of bullet jump to lands for other bullets.So back to my question, is this needed or applicable to handgun bullets? I am thinking that if i can get my OAL as accurate as possible for EACH handgun (i do this for each one), then i can start working on different powder loads to see what accuracy and velocity i can achieve for the best results. This is what i would use as my BASE so i have a start reference for any changes, including playing with OAL. PLEASE COMMENT
If you are using mixed range brass, sorting by headstamp may not ensure uniformity. Instead, sorting by resized case length would better help with ending up with more consistent OAL in terms of amount of bullet's bearing surface sticking above the case mouth when the rounds are chambered vs start of rifling.
bds,- MAX VS WORKING OAL/COL
- WORKING OAL/COL VS CHAMBERED OAL/COL
- WHEN TO USE SHORTER THAN MAX OAL/COL
- USING LONGER THAN SAAMI MAX LENGTH
- SEATING DEPTH - OAL/COL
- COMPENSATE FOR MIXED RANGE BRASS CASE LENGTH VARIATION
What you measured was leade or freebore, the distance from the chamber to the start of rifling. Many factory barrels have longer leade and slower start of rifling (angle is gradual) like Glock/M&P and most match barrels have shorter leade (or almost none like my Sig 1911 and latest Lone Wolf G23 40-9 barrel) and quicker start of rifling (angle is sharp).
The longer leade will allow longer than SAAMI max dimension rounds and I was told (by more seasoned match shooters) was a safeguard to reduce pressure (maybe for NATO spec +P rounds?). If the bullet has to "jump" greater distance to start of rifling, more high pressure gas will leak around the bullet and will compromise initial chamber pressure build. To maintain more consistent chamber pressure, you would need to use longer OAL, even longer than SAAMI max as long as rounds reliably feed/chamber from the magazine.
Yes, bullets will have different nose profile (ogive), even for the same RN profile and end up with different bullet base/bearing surface length which will hit the start of rifling at different OALs.
If you are using mixed range brass, sorting by headstamp may not ensure uniformity. Instead, sorting by resized case length would better help with ending up with more consistent OAL in terms of amount of bullet's bearing surface sticking above the case mouth when the rounds are chambered vs start of rifling. Can you picture that?
Depending on the bullet manufacturer, consistency of bullet nose profile will vary. Since it is the bullet's bearing surface that engages the rifling (and not the nose tip), using the same OAL with a particular random sample bullet may not ensure consistency of bullet jump to lands for other bullets.
So what are we to do to compensate for manufacturing variance and mixed range brass?
1. One thing we can do is using the same length resized cases (I guess using same headstamp cases can't hurt) and load a random sample dummy round to see at what length the bullet's bearing surface starts to rub the rifling when fully chambered and spun. Once the range is determined, we can identify the OAL that will compensate for bullet variance.
2. If you don't want to sort resized mixed range brass by lengths, you can also measure the range of variance and subtract the variance from the working OAL to compensate and use this length as your "Compensated OAL".
To conduct load development for my match loads, my bullseye match shooting mentor had me use same headstamp brass with same resized length but unless I am match shooting at top regional level, I don't think I would bother with sorting of resized brass. But to improve the accuracy of my range practice/plinking load, I would use the longest OAL that compensates for bullet/mixed range brass variance.
Only exception I would make is for 9mm bullets with shorter bullet base as insufficient bullet base seated inside the case neck may not produce enough neck tension for consistent initial chamber pressure build up. So with 115 gr FMJ/RN bullets, I use 1.135" OAL even though my max OAL is longer than 1.169". Even with 124/125 gr FMJ/RN bullets with longer bullet base than 115 gr bullets, I use 1.135" unless depending on the powder/charge, up to 1.160" to not compress the powder charge (Yes I know, some fluffy powders can tolerate modest compression without spiking the pressures). I have this issue mainly with 9mm and to squeeze optimal accuracy, it is a balancing act of reducing high pressure gas leakage vs consistent chamber pressure build.
If you look at the comparison picture below of MBC SmallBall loaded to 1.080", due to shorter but more rounded nose shape (see comparison picture of SmallBall to "stepped" Dardas/ZCast RN at bottom), the bullet base/bearing surface of the bullet will hit the start of rifling sooner than FMJ/CN bullets with longer nose.z7 said:How short is too short 124g MBC small ball?
On the mbc website it says load to 1.08" but with my lone wolf barrel they won't pass a plunk test until 1.04".
Alliant data for a 124 lead and be-86 oal of 1.12"
bds said:Large volume cases like .38 Spl with denser powders like W231/HP-38 (and even with fluffy powders like Unique/Red Dot/Promo), powder charge won't take up much space and will rest on the bottom of the case when the revolver ... is aimed. When the primer ignites, the flash will burn the powder charge from top down.Officers'Wife said:remember... Tulala on board. Powder forward?
The preferred powder charge burn is from end of case (primer end) towards the bullet for more consistent/even push that will improve accuracy. Some powders are more sensitive to this and they are called "position sensitive" powders (before someone objects, actually all powders can be position sensitive if low enough charges are used). For this reason, many reloaders will tilt the pistol forward/back to ensure powder charge is against the primer/bullet prior to slowly raising/lowering the pistol to fire. Some even use filling material to pack the powder charge so it is pushed against the primer.
I think some prefer the "powder forward" as the expanding gas from primer scatters the powder charge less instead of scattering the powder granule inside the case (some even warn against detonation/explosion from this).
W231/HP-38 is what I usually suggest to new reloaders as they usually won't load max loads and tend to use mid-high range load data and W231/HP-38 produces accurate loads even at mid range and meters very well.
Bullseye meters well but tends to produce snappier loads than W231/HP-38 because it is faster burning.
It produces accurate loads and "downloads" well (works below published start charges) to produce light recoil and accurate loads popular with Bullseye match shooters.
Titegroup meters well and produces accurate loads but has very narrow load range for some calibers/bullet weights and burns hot/violent and not friendly with some lead loads.
Red Dot/Promo produce accurate loads at lower cost point (especially Promo) and works well with lead loads but don't meter well and burns dirtier.
Unique has very wide range of caliber application and bulky to fill cases to prevent double charges but won't meter well.
I consider BE-86 the "modern Unique" with same burn rate that meters well and produces more accurate loads than other powders and recommend to new and seasoned reloaders.
WSF/AutoComp and other slower than Unique powders produce higher velocities than faster burn rate powders but require high-to-near max loads for optimal accuracy.
50cal, why such a tone?50cal said:I would caution anyone coming across this thread and thinking they have found the holy grail to reloading. It is at best a discussion on theory - some beneficial, some not so much. There is some 'meat' here but you need to sift through.
We have just started this thread and barely opened topic discussions. As far as I can tell, all the topics are in the "open discussion" phase. Before we conclude any topic discussion, I would certainly offer any further discussion or rebuttal to validate the range test results. Only then would I consider topic discussion successful and conclude with the "objective" findings in terms of holes on target from range test (and "objective" range testing is one of the discussion topics as "EVALUATING PISTOL LOADS" ).bds said:I am thinking of a group project thread that covers more advanced reloading concepts and ... freely discuss the finer details of reloading to squeeze out more accuracy ...
I am open to discussing theoretical reloading concepts but prefer verifiable concepts (reloading concepts that can be verified by range test/equipment measurement). Just because I post plausible concepts that "sounds" good DOES NOT mean they are factual (my wife is laughing ). I think we should treat all concepts as untested until we are able to test the concepts in real life. Keep in mind that holes on target are more factual and instruments don't lie like we do.
... After successful discussions, I can maintain an indexed summarized linked listings post with the necessary disclaimers Walkalong can be happy with
bds said:This thread is for reloaders who enjoy the minute details of reloading to OCD levels in pursuit of accuracy. If you are that person, come right in and post away. If utmost accuracy is not that important and minute of gong is good enough for you, read on.