Recoil

[chboats]

I finally got out to try some of the Mihec 432640 HP GC boolits. I had loads with three different boolits with me. Mihec 432640, 429244 SWC GC, and a Saeco Kieth SWC PB. the weights were 250, 245 and 255 (in order). They were all loaded with 20gr of 2400 and Federal 210 primers. The aloy of the two GC boolits was 11-12 bhn the Saeco Keith style was 24 bhn. The gun was a 44 SBH

The felt recoil from the Mihec was much heavier and sharper the the other two boolits. WHY???

The only real difference, that I can thing of, is the two SWCs have a much longer jump before the boolits engages the rifling.

Have not shot any of them over the chronograph.

Would not think there would be that much difference with boolits of about the same weight.

What are your thoughts?
Carl

[Az Rick]

Off hand the only thing I can think of might be the crimp. Obviously they are different boolits seated and crimped differently. Perhaps you got the Mihec crimped tighter.

Rick

Another thing might be the seating depth. Is there an equal amount of bullet in the case on each of the different boolits, one seated with more lead in the case will have more pressure.

[Edubya]

I would definitely go along with what Rick said about the seating but I kinda doubt that the crimp would make a noticeable difference on the recoil.

EW

[GP100man]

Yep , the keiths are big nosed with little less in the case compared to the Mihec.

I`m going by pics not actual boolits, It`d be nice to have a number on the difference from the crimp groove !!

[missionary5155]

Good morning
Like AZ said check the seated depth of the boolit . Seated deeper means more initial powder compresion which builds pressure faster. Fire the same 3 loads over a cronograph or carefully obsrve the primers.
I would not be surprised if the diameter of the MIHEC was larger. Take a micrometer or accurate dial caliper (they are not all accurate) and measure those diameters. .001 + wil make a difference in case tension and throat engagement which raises pressure.

[chboats]

Sorry it took so long to get back to you guys. Had Grand kid duties to take care of like football games and soccer games to attend to.

I checked the seating depth of the 3 different boolits. The 432640 was .050 to .060 deeper than the other 2. Measured the over all length compared to the boolit length to determin the actual seating depth.

As far as the crimp goes. I use a seperate die to crimp. Once I got it adjusted to the crimp that I wanted, it has never been touched. So all three loads used the same crimp setting.

missionary - I sized all boolits to .432 . The 2 SWCs started out at .433/.434. The Mihec casts dead on .432. I am sure there are differencies in the case tension beacuse of the differencies in the surface area of lead and GC in contact with the case. The primers in the Mihec boolits are flatter than the other loads.

Next time I get out to the range I need to take the chrono out to see what they are actually doing.

for what ever it is worth the Mihec boolits are the most accurate.

Thanks for the inputs. Will keep you posted.

[white eagle]

might be the Mihec boolits fill the bore betta and uses the gases moe betta
pushin the boolit

[MtGun44]

Smaller combustion chamber will raise pressures - definitely. Keith tried to get more boolit
out of the case to leave room for more powder.

Bill

[cajun shooter]

The difference in felt recoil was the alloy used. The Mihec bullets were 11-12 BHN and the Saeco was 22BHN which is Linotype hard. The Mihec bullets obturtated and filled the bore thus keeping all gases behind the bullet. This load doing it's job with more felt recoil. The Saeco with it's very hard bullet did not fill the bore and allowed gas by it causing it to feel less powerful.

[Changeling]

The difference in felt recoil was the alloy used. The Mihec bullets were 11-12 BHN and the Saeco was 22BHN which is Linotype hard. The Mihec bullets obturtated and filled the bore thus keeping all gases behind the bullet. This load doing it's job with more felt recoil. The Saeco with it's very hard bullet did not fill the bore and allowed gas by it causing it to feel less powerful.


If that were true wouldn't the Saeco bullet have caused severe leading by letting "Gas" by?

[chboats]

The Saeco was a non check boolit and WD. The other two were gas checked 11-12 bhn. The Mihec boolit was a RNFP the third boolit was an SWC 429244. Some leading was encountered with the Saeco SWC. All were sized at .432. The barrel grove diameter is .430.

Carl

[cajun shooter]

A GC has been shown to not interfere or keep a bullet from the act of obdurating in the bore of a gun. You had leading with the Saeco. I think my answer is as good as my pay grade. Anything more will have to come from someone who has more studies in the internal ballistics; if it were possible maybe some one like Werner Von Braun.

[buck1]

My Mihec 432640 kicks a little harder also, Alloy , size ,and the load I worked up to are the same as my others. Primers and extraction seem fine.

[chboats]

cajun shooter - I was not saying you were wrong, because I don't know why there is such a big difference in the recoil. The only reason I put up the last post was because a couple of the poster were comparing the Saeco and the Mihec difference in hardness. The Lyman 429244 an SWC also was soft like the Mihec but had the same recoil as the Saeco. The difference in recoil may be a combination of several things, I don't know.

I was just wondering because I know there is about a billion times more experience on this forum than I have.

Carl