superdude

An article on the brass: https://www.ssusa.org/articles/2019/7/23/rimless-38-super-brass-everything-you-need-to-know/

Might be useful information here: https://www.ssusa.org/articles/2017/6/26/how-to-clean-tough-lead-deposits-from-your-barrel

A couple possibilities: https://www.ibejiheads.com/product_info.php?cPath=3&products_id=41&osCsid=7baf0539d9042abaad4c88bb22ad3927 https://missouribullet.com/details.php?prodId=232&category=20&secondary=13&keywords=

Different bullet shapes require different overall lengths to fit in the chamber. The diameter is fine, and is typical of lead or plated 9mm bullets.

With these examples (in a 2 pound gun, zero weight for powder) the 147 grain will have more recoil. 124 @ 1050 fps = 2.69 ft lbs recoil 147 @ 1000 fps = 3.43 ft lbs recoil

First, you can plug those numbers into a calculator to determine recoil force. http://kwk.us/recoil.html Second, if bullets of different weights are pushed to the same power factor with the same powder, the lighter bullets have more recoil. https://www.shootingtimes.com/editorial/power-factor-recoil-bullet-weight-gives-edge/99399

https://www.snscasting.com/

Which bullet manufacturers?

Send your photo to Lee.

There's almost always a little variation in seating depth. Sometimes it's minor differences in the bullet nose. There's not much you can do about that. Progressive presses are more inclined to produce variation as well since there is a lot of stuff going on that can affect shellplate tilt. I would not be concerned with .002-.006 variation. If the rounds fit, feed and shoot well for you, there's no need to change anything. If there is any change in accuracy with .002-.006 variation, and I doubt there is a meaningful change, you would need a super-accurate gun, super accurate ammo, and test it in a Ransom Rest. And the difference would likely be in fractions of an inch, or otherwise a meaningless difference. Even when accuracy testing, group sizes will differ with the same ammo. This makes it challenging to see minor differences in ammo even under the best of conditions. Here's an article on looking at group size that you might find of interest: https://www.ssusa.org/articles/2019/9/25/accuracy-testing-shortcomings-of-the-five-shot-group/

You might find this article of interest: https://americanhandgunner.com/gear/crooked-seated-bullets-and-accuracy/

That's right. They are not oversize beyond SAAMI specs. But you said, "OK let me ask the same question a different way: hasn't it been shown by many 929 users here that it has a bore that is oversized compared to 9 mm bullet dimensions?", saying that 929 barrels are oversize for 9mm bullets. 9mm barrels are oversized compared to 9mm bullet dimensions in the same way that 929 (or 38/357) barrels are.

As noted, 9mm and 38/357 barrels have the same SAAMI barrel specs. I've slugged 17 9mm barrels. The average was .3566". The smallest was .3553, the largest .3578. The nine 38/357 barrels I've slugged had a average of .3561. The smallest was .3532, the largest .3577.

9mm barrels are oversized for .355 bullets, too.

9mm and 38/357 have the same SAAMI barrel specs; .355" + .004" groove diameter. https://saami.org/wp-content/uploads/2019/02/ANSI-SAAMI-Z299.3-CFP-and-R-Approved-2015-12-14-Posting-Copy.pdf

You might find this link useful: https://www.ssusa.org/articles/2018/1/9/how-to-use-9-major-in-a-short-barrel/ Some commonly used powders for 9 Major are in the tables.

Hodgdon's 'conservative' velocity is because of the short OAL. That raises pressure. The pressure is 33,600 psi which is getting close to the max 9mm limit of 35,000.

As noted, you'll have to determine the OAL required for each bullet you use. This figure shows the 'just fits' OAL for several different bullet designs in a CZ barrel;

I'm not sure you need to match the barrel's .356 with jacketed bullets. Barrel specs for 38 Super (and 9mm and 38/357 revolvers) are a groove size of .355 to .359. Undersized jacketed bullets shoot very well through them. For example, I've Ransom Rested 9mm handloads through a Ruger Blackhawk revolver with a conversion cylinder and a .3577" groove diameter barrel and produced very small groups with .355 jacketed bullets, including 24 shots in 1.40" at 25 yards. Other .355 bullets were as accurate as, or better than, .357 bullets. If matching the barrel dimensions is required by jacketed bullets, my data does not agree with that. Lead bullets might be a different story and undersize lead might contribute to leading. I've not tested that so I can't say.

Compensators work very well with ALL bullet weights. Lighter bullets work a bit better. https://www.shootingtimes.com/editorial/power-factor-recoil-bullet-weight-compensators/99206

A couple things. . . If bullets of different weights are pushed to the same power factor with the same powder, the lighter bullets will produce more recoil force. Light bullets must go faster than heavy bullets to achieve the same power factor, so they accelerate faster and spend less time in the barrel. This means a faster recoil impulse. The light bullets' shorter barrel time and additional recoil likely combine to make their recoil feel different from heavy bullets. Source: https://www.shootingtimes.com/editorial/power-factor-recoil-bullet-weight-gives-edge/99399

https://www.vihtavuori.com/powder/n330-handgun-powder/

N105. A#7. Silhouette. A#9 would also work.

With luck your new gun (barrel) will have a long throat to allow you to load long = ~ 1.150 or so. That's the trick to help keep pressure low. See the last link (ssusa) posted by TheChewycookie. It has 9 Major load data with your 3 powders and 125 HAPs.

The softest feeling recoil impulse will be with heavy bullets. The supposed reason is that they accelerate slower because they don't have to reach the same speeds as lighter bullets - especially for the same power factor. An alternative is to simply load the 125 grain bullets to a lower speed.