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Topic: Which First Bullet Seating or Powder Charges (Read 573 times) previous topic - next topic

Re: Which First Bullet Seating or Powder Charges

Reply #15
This sounds suspiciously like a problem I ran into. My brass had developed a donut such that even fired brass would have "feel" when lifting the bolt (firing pin and ejector removed). It got worse; bumping the shoulder 2 thou still had the same feel. Just to be clear, this is without seating a bullet, it was just the brass.

I'm no expert but you shouldn't have to seat regardless of true CBTO unless you are up against feeding constraints.
I agree on your point of a stiff bolt with fired brass. But first, I forced the bolt close to chamber a live round. Figured that was not a good idea to shoot the round because of pressure considerations (shouldn't have to force it into the chamber). THEN I had trouble lifting the bolt and unchambering and ejecting on a live round. It took a lot to get it out the chamber. I will not force another round like that again.  Learned my lesson.

Re: Which First Bullet Seating or Powder Charges

Reply #16
I agree on your point of a stiff bolt with fired brass. But first, I forced the bolt close to chamber a live round. Figured that was not a good idea to shoot the round because of pressure considerations (shouldn't have to force it into the chamber). THEN I had trouble lifting the bolt and unchambering and ejecting on a live round. It took a lot to get it out the chamber. I will not force another round like that again.  Learned my lesson.

Fair enough, you know what's going on in real time, I'm just hazarding a guess :)

That said, the only time I had a bolt closing problem was because of a defective FL sizing die that was ruining the brass.

 I guess my thought is if the bullet is seated such that you are jamming it into the lands, at worst you have a decent bullet puller on your hands. Jammed up brass is another matter,
Chris

 

Re: Which First Bullet Seating or Powder Charges

Reply #17
As mnbogboy suggestead take a sharpie and paint that round thats causing problems from base to tip and chamber it.. it will scrape off the sharpie wherever its binding and causing problems... once you see where the problem is then you can fix it..
Grant

Re: Which First Bullet Seating or Powder Charges

Reply #18
Back to the original question..... Powder charge first or seating depth?

For years I always felt that finding the powder charge first and then fine tuning that load with seating depth was the best course of action.  In the past year I have had a couple of problem children chamberings that would shoot real well in general but go out of tune at times and give a few fliers each match...which will kill any chance of a win or top 3 typically in F-class as well as BR.  I am in the beginning stages of developing a load in a new (to me) cartridge.  Being an improved cartridge it must be fireformed from one dimension (short bodied 7 SAUM case) into the & Sherman Short mag which is a change of about 5gr of water capacity.  I decided to go the route of first finding a solid and forgiving seating depth.  I chose an arbitrary powder charge based off a friend's fire forming load with a similar weight/style bullet and 'broke in' the barrel with a shoot 5-6/hard clean, rinse repeat 2 more times using an arbitrary 0.010" off the lands.  I then shot, at 100yds, 0.010-0.060" off the lands testing in 0.010" increments and 10 shots each and found that at 0.040"-0.050" off the groups were decidedly tighter and NO bullets out of the group in those 20 shots.  I then loaded 6 rounds of 0.035", 0.040", and, .045" OTL and retested.  the last two depths were both about the same- 0.40-.41" at 100yds and the first about 0.51" with all shots touching the groups..ie-no fliers.  I now have a solid seating depth well off the lands that I will then use for powder charge testing in formed cases.  This is the first time I have stuck to this protocol and am interested to see what shakes out.  This was suggested to me by a couple of fellow competitors in F-class that have national championships to their credit but I have always bugged out because most of the shooters I associate with regularly stick with what everyone else is using for seat depth..."THE known depth for that bullet".   What I did find is that the closer depth of 0.010" off, which is within 0.005" of what almost all shooters I have asked suggest for this bullet had a sub .4" central group but out of the 10 shots one kicked high and one kicked low not touching the central group opening it up to about .9".   I don't want a seat depth that is a few thousandths away from disaster shooting in a match; I find those loads finicky and apt to drop out of tune during a day or week of shooting.  So far it appears I have a good broad depth range where the load is at and below .5" grouping over 30 shots/0.020" depth range and tighter than that with finer depth testing over 0.010" depth range.  Now I feel that I can began valid powder charge testing and, once I have a charge that shoot small over .5gr+ range, I have a high degree of confidence that it will have a broad tune window for varying conditions.  Will this load produce the tiniest groups at any given time?  In my experience not likely but my loads that have shot very small groups at distance also would not reliably shoot small enough over a wide range of conditions to keep me in contention for a win in F-class.

Note- I chose 10 shot groups for preliminary/coarse testing ONLY because I had to fireform a bunch of brass and it was very convenient to do so while getting this test accomplished.  For a coarse test 4-5 shots would be plenty.

Re: Which First Bullet Seating or Powder Charges

Reply #19
Back to the original question..... Powder charge first or seating depth?

For years I always felt that finding the powder charge first and then fine tuning that load with seating depth was the best course of action.  In the past year I have had a couple of problem children chamberings that would shoot real well in general but go out of tune at times and give a few fliers each match...which will kill any chance of a win or top 3 typically in F-class as well as BR.  I am in the beginning stages of developing a load in a new (to me) cartridge.  Being an improved cartridge it must be fireformed from one dimension (short bodied 7 SAUM case) into the & Sherman Short mag which is a change of about 5gr of water capacity.  I decided to go the route of first finding a solid and forgiving seating depth.  I chose an arbitrary powder charge based off a friend's fire forming load with a similar weight/style bullet and 'broke in' the barrel with a shoot 5-6/hard clean, rinse repeat 2 more times using an arbitrary 0.010" off the lands.  I then shot, at 100yds, 0.010-0.060" off the lands testing in 0.010" increments and 10 shots each and found that at 0.040"-0.050" off the groups were decidedly tighter and NO bullets out of the group in those 20 shots.  I then loaded 6 rounds of 0.035", 0.040", and, .045" OTL and retested.  the last two depths were both about the same- 0.40-.41" at 100yds and the first about 0.51" with all shots touching the groups..ie-no fliers.  I now have a solid seating depth well off the lands that I will then use for powder charge testing in formed cases.  This is the first time I have stuck to this protocol and am interested to see what shakes out.

(abbreviated for brevity...)

This is as close to a parallel argument for longer jumps that I have seen here on the Creedmoor Forum after the articles published on the Precisison Rifle Blog (https://precisionrifleblog.com/  from Mar 21 thru Apr 28) addressing experimentation on this subject.

Re: Which First Bullet Seating or Powder Charges

Reply #20
I read that a few weeks back which also paralleled what the two shooters suggested as a load development pathway.  Both are well known and have authored articles, and one books, related to rifle load accuracy and ballistics and are associated with Berger.  I am hardheaded and figured I'll stick with what works....until it don't anymore ::) .  It must be the cajun in me ;) .

Re: Which First Bullet Seating or Powder Charges

Reply #21
robin it will be interesting how close your final charge weight is to what you tested seating depth at... im betting really close...
Grant

Re: Which First Bullet Seating or Powder Charges

Reply #22
I've always done powder charge first, seating depth second. Never had a problem finding accurate loads with that process.
Tarasdad - NRA Endowment Life - TSRA Life

Re: Which First Bullet Seating or Powder Charges

Reply #23
robin it will be interesting how close your final charge weight is to what you tested seating depth at... im betting really close...

Grant, It will be a likely bit different as the seat depth test was in unformed cases with a large volume reduction compared to the final form.  I shot a single shot in a formed case using a 190 A-tip for velocity just to get an idea of where to start my charge weights.  The load with 60.5gr H1000/190 Atip 0.030" OTL I had 2604 fps MV.  In the brand new barrel/new unformed cases with 57.5gr H1000 I had 2509 fps MV.  I am hoping to find a great grouping load somewhere between 2600 and 2800 fps as the bullets will shoot inside of a 300 WSM/215 hybrid/2950fps at the low end of 2600.  I think I will be within 2gr for the same velocities in the formed cases.

Re: Which First Bullet Seating or Powder Charges

Reply #24
I've always done powder charge first, seating depth second. Never had a problem finding accurate loads with that process.

Me too.  However, when shooting 80+ rounds a day in ever changing conditions and finding a gun that is nailing the X-ring in the morning and is popping 9's out the top/bottom with a perfect wind call in the afternoon it means my load was tuned in a narrow window.  I feel, based on my experience, that I could have a more condition tolerant load if I have a forgiving seating depth.  If I can pull an arbitrary charge weight out of my arse and work out a seating depth with a broad range of precision then I expect that load to be forgiving and really hammer once my charge weight testing is done.  I'll see in the next week if my expectations are met.  Preliminary results prior to working up a charge weight are looking really good.

Re: Which First Bullet Seating or Powder Charges

Reply #25
I've always liked to do a powder ladder to look for an area then do a seating so my following powder ladders were at a good seating depth.
Dave

Re: Which First Bullet Seating or Powder Charges

Reply #26
This is a pretty old debate!😂. I’ve argued for both sides of the fence in the past and still don’t feel there is a correct answer when the question restricts you to one way or the other. Robin’s point is really valid. You should look for the widest node in both variables but don’t stop with a two step process. I am most comfortable doing charge first followed by setting depth. Don’t think it’s a good idea to take the first one that looks good but push the envelop and find a broad range in depth that performs. Once that is found I make it a three step process and go back to tweak the charge using the good seating depth range for a final combo.

Re: Which First Bullet Seating or Powder Charges

Reply #27
I know this may not be the same for everyone but, it would be much easier for me to field test seating depth than charge weight. The range I shoot at has a public reloading room with a Forster CoAx press available. I could seat to jam, or jam +, bring my own die and fiddle with seating depth quite easily. I'd be pretty confident about the actual seating depths without hauling delicate, sensitive, or otherwise difficult to transport equipment. On the other hand, the public powder throw equipment is not something I have any confidence in, and there's no way I'm hauling my powder throw equipment to the range.

I'm reconsidering my charge first, seat next approach just from this practical standpoint. It's not easy since I've always done it the other way around.

The implication of course, is that it's just as easy to pick a "generally good" charge to start with as it is to pick a  "generally good" seating depth to start with.

I think the reloading manuals are what set the tone; here's your COL, play with charge.

Chris

Re: Which First Bullet Seating or Powder Charges

Reply #28
Nice work @rardoin

I've noticed since I started NOT doing it exactly the way all the pros were telling me to do it I started having some success. I'm not insinuating anyone was intentionally leading me astray and to the contrary they all were trying to help but until I admitted it wasn't working and put some tweaks on it there was little joy to be had.

We all pay our own dues and must develop our own process to find success.
Competing at Match winning levels requires a commitment to testing few have. If I'm wrong about this how come the same guys keep winning?  Barrels get shot out in a season or less because of the testing not the matches.
A developed process that doesn't have the desired result needs changed until it does. Hard to do sometimes but if it's not working we need to let go and change.
Robin has always had a "stated out loud accuracy requirement" tested AND measured on paper which in my opinion is the only way to track success and quantify changes to the process.

Identifying improvement is impossible without accurately measuring it.


 
Dave

Re: Which First Bullet Seating or Powder Charges

Reply #29
More data.  I loaded up fire formed cases with an arbitrary charge (fired one shot into a stump with a Magnetospeed on a 'guestimated' charge H1000 60.5gr with a 190 A-tip gave 2800fps) for a seating depth test at 100yds because again too windy to go out further without skewing results too much.  I started at 0.010" off out to 0.060" off in 0.010" increments just like the last test in the new cases with the 190 Berger LRH.  Shot without flags but did have some foliage to watch for the big puffs.  Wind was 6-8mph g12 from L>R about 90deg.  Far from ideal but I am itchin to get this Sherman running.  I shot over a Shotmarker e-target.  Looks like this thing wants to shoot the A-tips too and is forgiving on seating depth well OTL.

0.010" OTL


0.020" OTL


0.030" OTL


0.040" OTL


0.050" OTL


0.060" OTL